sorry i didn't read all the posts but,
since you have a mac book pro and im guessing your pixels per inch is like mine which is at 110, ill tell you my opinion.
the last time i checked the 23in it was at like 98 or something and i just checked the the 24 in and its at 94.
ok this is my opinion as i have tried 4 different displays and spent hours trying to find one.
anything under 100 pixels per inch is crap. i mean really bad.
if you are going to use this as an extended desktop then its horribly annoying.( a picture on your mbp if you measured it with a ruler ,ie ruller to screen, the picture could be 2x2 but on the other display its 3x3)
try and get something around 104.
thats the highest i could find in a flat panel
the only size display that has anything decent is either a 30in or 19in.
trust me i have checked way to many displays on this.
mine is 19in.
and it is from westinghouse and was 150.
best display i could have found i think.
heck if there is better i would love to know.
but untill i get a nice bank roll ill role with 19in's, even if i buy like 3 of these.
edit,
you can check the pixels per inch by just googleing "pixel per inch calculator".
basically resolution is the only thing that i found is worth looking for (to put what i said in a few words, that are understandable)