I thought the 27" would be too big as well but with the thin bezel to it all you get is the screen and it feels like a nice fit for the swift.
Have been on 27" monitors for 3 years and now feel this size is getting small for me. Next one will have to be 30" on up. Currently have 1440p and 1080p 27" displays. Pixels on the latter are visible for me on the desktop and is what prompted me to go 1440p. But in movies or gaming you will be hard pressed to notice it. Monitor size is paramount to me and contributes hugely to immersion and visual impact, so would take a good 27" 1080p over a 24" any day of the week.
Will this be reviewed so we can find out if Acer have used the same panel as the ASUS? Would like to see a side by side comparison of the ROG Swift PG278Q vs the Acer XB270HA and see which one comes out tops, would be nice to see the cheaper Acer pwn the ROG Swift! Unfortunately I still love my 24" Dell U2410 too much to change. I have mine about 50cm away and don't notice the 'lego' effect by sitting too close! Plus, i'm adding a 2nd GTX780 to my rig next week so that's my budget gone for a few months anyway.