Hey,
For me, the G5 (32"/2K) replaced my older three 27 "s and I was "blown away" ;) At first I was almost a little overwhelmed by the size, but you get used to it very well *grin*. The colours are rich and the monitor can be adjusted well via the HUD. The only downer I've noticed so far is the reflection. Depending on the incidence of light, it reflects relatively strongly and the colours become fake. But since I'm more of a gamer, it's almost always dark for me anyway ;) . I can't say anything about the Acer one because I don't know it in action or otherwise. But I would definitely recommend the G5, if only because of the price/performance ratio. The only thing was that I couldn't use all three monitors properly (that they all ran at the same time) until I bought slightly more expensive 1.4 DP monitor cables. The older ones I had didn't seem to do well with the 144Hz and 2K.
Hope this helps you a little.