I work with both 30" models, and i can safely say that the Dell A04 revisions are the nicer monitors. If you get one of the older 30"s then it's pretty average, and there can be some clarity issues, but the new revisions are fantastic. The apple one's aren't bad, but they dont' justify the price tag.

Like someone already mentioned, i'd go with dual 24"'s if i were you (i have them on my home computer). It's far more effective, and you get way more real estate. It also depends a bit on what you'll be doing with them.