>>1419312size is dictated by use. I do a lot for painting cg and 3d work so larger the better and more pixels as possible. I prefer the 16:10 since it provides more vertical pixels and is not so odd when rotated. Many app I use are designed for 1200 pixels high, and 1080 is just too short, so menus end up chopped off (try using sai on a sub 800pixel high screen) I could probably live with a 27" with 16:9 since it retains the height. But the size is not that comfortable at times. Same goes for 30" Having that 8 in from your face is a bit overwhelming. Gaming on a 30 though wow.
Specs I guess the panel type and screen surface are biggies. Some like matte others like gloss. I hate gloss but some screens matte finishes are wtfh. % of gamut is important too for heavy graphics. One of my screens is one of those 10bit things with the extended gamut. Pros and cons on that. For me it is a PITA to calibrate, still rage at getting it to match up to my other 24" So for now I recommend sticking to the 98% to 100% units. Also make sure it has a internal controller, seen a lot of screens that lack HDW controllers and rely on craplets to adjust shit through software which is CRAP vs physical HDW adj. IE simple crap like brightness contrast etc are software only. GFX card should process and output exactly what it is fed not dick with it prior to it going to the lcd. (loath gfx based adjustments to color etc)
Ok either way it is probably best to google about and find a turbonerd forum on lcds
