Awesome, I submitted my thoughts. Personally, G-Sync is cool but not a priority for me. My main requirements when I'm looking at a monitor are 1. color quality (especially blacks, so local dimming is important for LED backlit monitors) 2. PPI (preferably highest resolution possible in <=24", so 4K in 23.8" such as the UP2414Q is nice) 3. Minimal input lag 4. Refresh rate (minimum 60Hz, preferably higher).
Currently from what's available on the market my next monitor is probably going to be a UP2414Q, but I'm waiting to see what else hits the streets. I'd much rather shell out a little more dosh for an Ezio vs a Dell though, because I've been extremely impressed with the professional displays Eizo makes and I think a solid gaming monitor from them would be better than anything I could buy from anyone else most likely.
As far as cost considerations go, I consider a monitor to be one of the most important parts of my overall system. I will happily shell out $1k+ for a quality monitor and if needed build a system around driving it capably. At the end of the day, computers are just input/output devices. So input peripherals and output peripherals are the most important parts of the system.