I had to install the properitary NVidia drivers but it kept locking the entire machine, sometimes 30 seconds after booting, sometimes a few minutes. Took hours of restarting and trying to get the drivers installed before it would hang to get it stable.
Since getting them installed it's been solid.
I'd now like to upgrade to 20.04, but not if I need to go through the whole ordeal of racing to get drivers updated before the system crashes.
The biggest issue I can remember was weird issues with the graphics drivers a few times. Not quite sure exactly how it happened, but apparently I had a pretty wonky installion at first. I uninstalled and installed the nvidia drivers through `apt`.
Other than that, I have an unsolved problem of random, occasionally reboots, mostly which conveniently happen when I'm away from the PC. Everything goes back to normal after rebooting and it usually doesnt do it again for a while. I havent managed to solve this, but I'm assuming it's a rather localized problem.
For me; my Razer Nari wireless headphones just don't work. They're not bluetooth; they have their own low-latency USB receiver, and thus their own Razer-supplied drivers, which are not available on Linux. There's been some effort toward getting Razer products working better in Linux, but (last I ran Ubuntu, a few months ago) their headphones are not there yet.
You just have to try it out and see what works, see what doesn't. Chances are, it'll work fantastically for you.
I have no issues except for a driver issue for the audio chip on my mobo (Gigabyte Aorus Master TRX40) that seems to only affect optical audio out.
Cooling solution, RAM, and monitors aren't things that will have OS compatibility issues.
Ed: i would probably go straight for 20.04 on a fresh install - but heed sibling comment about nvidia drivers. Might run fine on open source drivers until proprietary ones gets an update (fine, but slow).