To give some balance to zombie's post:

Nvidia's drivers are good right now, with excellent performance and there's no reason to think it will change in the future. AMD is often late with drivers for new hardware and performance is highly debatable, often requiring users to install pre-release Mesa and kernels to have a functioning card at all. Installing and updating Nvidia drivers is done through the package manager just like AMD's and is equally painless. Plus, there's no need to update parts of the system through unofficial channels to have your card running well.

If your friend is going to run Windows titles through Steam Play, DXVK recommends at
least 8 GB of video memory. Running out of memory is a big problem on 4gb cards.

i would really love to use a amd card, but in my eyes in its current state it is not as smooth as running a nvidia card.
I built a PC and bought a used RX580, all good after adding ppa for mesa and ukuu for newer kernel, then all runs good, but as soon as you want do do some little tuning, like undervolt, or just handle fan,...... its in my eyes a pain in its current state, i wasted days to get it how i wanted it. Also i had heat issues in my ssfpc, so i decided to replace it with a used GTX 1070, since then no overheating issues, but the best thing was, install the driver and use the nvidia settings were all is in what i need, done in minutes.
I really would love to switch again to AMD Gfx and as soon as they get their stuff together i will, but currently i have to say i am happy with Nvidia even when i don't like them.

The way I see it:


NVIDIA:

Pros:
- better value for the same price
Cons:
- proprietary drivers
- more likely to have issues during installation

AMD:

Pros:
- open source drivers
- works out of the box with most distros
Cons:
- less supported for Linux native games (example: https://support.feralinteractive.com/en/faqs/mesa_support/)

I like AMD nothing is holding me back from running the latest kernel, updating the drivers is just trivial. With NVIDIA you are stuck with older kernels. With the work done by valve and other companies, there is a lot improvement potential on the AMD drivers, most likely AMD drivers will improve in the upcoming years and NVIDIA will just stale.

As for performance AMD counterparts are on par with NVIDIA, so if you are not going for the high end, where NVIDIA has the lead, on the mid-range and low range AMD it's the clear choice (imho).

stuck with older kernels, really?. There have been few issues with rc kernels, but you can still patch the drivers for git builds. Anyway, with up to date release kernels, i never experienced any issues with drivers, you just have to have the latest drivers for latest kernel/xorg. Aalso you don't usually need git kernels with nvidia as they dont give you anything, with AMD you likely need, because of added features/improvements etc.


I'd say Nvidia is more pain free on Linux. Install the distro, Install the drivers and be done with it.
With AMD there are so many combinations of drivers, LLVM versions, Gallium, Mesa all the mess, to get up to date.
That being said, i think in midrange AMD is still pretty good. Navi GPUs specially, but they need some driver improvements first. Polaris seems way too powerhungry for its perf, compared to competition imo, but if the price is good, then polaris cards are pretty good.

AMD:

Cons:
- less supported for Linux native games (example: https://support.feralinteractive.com/en/faqs/mesa_support/)

It's important to distinguish between "not supported" and "doesn't work" - I have nearly every Feral port and they all work with Mesa now. A lot of the "not supported" in that list was when Mesa was missing certain OpenGL extensions or whatnot years ago.

In practice, there's only a handful of games in my several hundred steam game library that don't work or require a Mesa-specific workaround. So long as you have a recent kernel and recent Mesa you should be good to go.

As for performance: radv is excellent and if you look at benchmarks on Phoronix and other sites, AMD cards are competitive with their Nvidia offerings in their price range save for the really high end range.

With AMD there are so many combinations of drivers, LLVM versions, Gallium, Mesa all the mess, to get up to dat.

The only time you need to worry about LLVM is if you're compiling from source. On Arch it's as simple as installing the Mesa package and the vulkan-radeon package. What else would you need?

I'd recommend to wait a bit, if that's an option, and then get one of the new Navi cards using custom, not reference design. By the time custom design cards will come out, kernel and Mesa will be in better shape. Navi are really the best cards AMD offers, and especially AMD RX 5700 XT is enough to play even demanding games at 2560x1440 with very good framerates.

AMD:

Cons:
- less supported for Linux native games (example: https://support.feralinteractive.com/en/faqs/mesa_support/)

This FAQ looks very outdated, referencing some ancient and obsolete versions of Mesa, so it's not relevant today.

The notion that Mesa has less supported games today is simply incorrect. Mesa developers gradually fixed most issues that affected older games. Overall, Nvidia doesn't have less issues than AMD, including for new games.

@Xpander

of course nvidia drivers solution is less than ideal, if I want to run a newer kernel than the default (4.12) on OpenSuSe, then getting the packages from the Nvidia repo will not work. That's what I was referring to.

I mean really?? they only provide support for the (ancient) 4.12 kernel on OpenSUSE?? it must be a bad joke, I like to run old kernels but not _that_ old, the 4.19 lts branch is already point 58 release. Is that the best NVIDIA can do??

no idea about suse, but running kernel 5.2 and nvidia 430.26 for last 5 days without issues.

I recently upgraded my old PC that was Intel and NVIDIA to a AMD build.

So I had:
Intel 3rd Gen Quadcore at 4Ghz
NVIDIA GTX 1080

I now have:
Ryzen 2700x
AMD 580

I basically bought the 580 just to test out the experience with the opensource AMD driver. I was planning on switching back to my GTX 1080 since that card is more powerful but the opensource driver experience was so much better with AMD that I went with a lesser card.

The experience with the AMD driver on Linux is also better then NVIDIA. NVIDIA isn't bad but it had some quirks with my triple monitor setup and with AMD I had no issues there.

Performance wise, NVIDIA is better, but AMD is a better fit with Linux.

@Xpander

of course nvidia drivers solution is less than ideal, if I want to run a newer kernel than the default (4.12) on OpenSuSe, then getting the packages from the Nvidia repo will not work. That's what I was referring to.

I mean really?? they only provide support for the (ancient) 4.12 kernel on OpenSUSE?? it must be a bad joke, I like to run old kernels but not _that_ old, the 4.19 lts branch is already point 58 release. Is that the best NVIDIA can do??

Nvidia has a repo for tumble weed that supports the newest kernels. https://download.nvidia.com/opensuse/tumbleweed/.

I myself think nvidia is the better option as at least a few major linux ports of games don't support AMD cards

I myself think nvidia is the better option as at least a few major linux ports of games don't support AMD cards

Used not to support. That was mostly fixed already by Mesa developers - they explicitly asked to collect such list and worked on fixing those cases. Those were mostly low quality ports, that lost support from original developers soon after release.

See:

* https://www.gamingonlinux.com/wiki/Mesa_Broken
* https://www.gamingonlinux.com/wiki/Games_with_recent_fixes_in_Mesa

If you know something that still doesn't work and not in the first list above, please add it.

Thank you all so much for the great comments! I have been away for a few days so I haven't had the chance to post earlier.

You have given me a lot of information I haven't had before. It still is a tough decision!

It will for sure become a Ryzen based machine, as far as I know, and a midrange card. I will post the decision here shortly. Thank you all again!

After looking at the prices and all that, I think an RX580 is indeed a good choice. I haven't seen a better card for that price. And if there are no huge differences anymore, compatibility wise and regarding driver support, it might be well worth it to give it a try.

I will keep you updated about it and some testing results I will be doing, comparing it to my own 1050 Ti.

Thank you again for all the info, you are awesome.

Be careful about the brand though, some 580 cards have issues regarding cooling and noise.
If I may, give Sapphire cards a try, I have a Sapphire Radeon RX 590 Nitro+ and it behaves really well, review here: https://www.pcworld.com/article/3323380/sapphire-radeon-rx-590-nitro-review.html
If you can find one of these (they go for similar prices) go for it.

As for AMD/Nvidia drivers, really, you'll be fine fine with both, don't listen to the banter.
If you go for Nvidia I would suggest the GTX 1660 ti, is the second best in terms of performance per dollar.

Some numbers regarding temperatures, power consumption and performance per dollar for both cards:
https://www.phoronix.com/scan.php?page=article&item=nvidia-gtx1660ti-linux&num=7