I can't lend an opinion on brands, but it does sound like the current market is pretty bad overall with plenty of reports of poor back-light uniformity and dead pixels. Hopefully others can chime in with their experiences, though it would be easier to look at reviews and customer testimonials for specific models with the features you're interested in. I bought a second hand Benq xl2730z earlier this year and it's great, I've no issues with it at all, but I don't know if that's normal and I believe most issues are with recent IPS panels, plus the monitor is EOL and they all look pretty overpriced new.
I had an AMD card for a brief period that allowed me to try out freesync on my monitor. I hadn't been bothered about having it before and tearing is virtually impossible to see at 144fps/Hz anyway, so it wasn't a night and day difference to me as reading other opinions make it out to be. So personally I don't think it's worth paying extra for. Due to your GPU my suggestion is to look at the games you currently play / hope to play and find out if you'll be CPU bottlenecked in any of them, because that's the only thing that's guaranteed to stop you from smashing those frames, unless you really must have every setting turned up to the max regardless of it's impact or visual improvement.