I'll second that, having got a Dell U2711 on my new 2011 mac mini server.
In comparison to the Apple TBolt display (which in fairness I haven't used, but have lusted after before getting this)...
Need separate displayport (or one of the other video interfaces, but i'm using displayport) and USB leads. Messy.
Doesn't have speakers. Dell speaker bar is good though, but it's extra. It clips onto the bottom of the screen, power plugs into the monitor, and audio plugs into the monitor's own line-out socket given audio goes into the monitor via displayport or hdmi. But the long speaker lead on the speakers still has to loop around somewhere back there. Messy.
Doesn't have a webcam/isight. I didn't want one so no loss to me (if I did, it might have tilted me to the apple). If you want one, you gotta clip it on somewhere. Messy.
No ethernet or firewire interfaces that the tbolt monitor has. Nor of course the ability to daisy-chain that tbolt itself offers. So you'd still need separate interfaces/hubs etc. scattered around your desk to give you that. Messy.
No power-out for a laptop. Doesn't bother me as mine's a mac mini and you can't plug those into a magsafe (another thing that might have swayed me to the apple monitor if you could). So if you *are* using it with a recent apple laptop, there'll be an extra lead trailing around. Messy
I think there's a theme there.
Cheaper. I paid £589.00 from aria.co.uk, which was persuasive.
Stand is more flexible. Apple stands can only tilt (no swivel contra the review, although that may have changed in a way the picture doesn't reveal). Dell stand tilts *and* swivels and has height adjustment too, and is in fact basically a vesa stand, and monitor easily vesa-mountable. (Apple's is with an extra kit.)
More inputs. You can only plug the Apple into a machine with a displayport or a thunderbolt port. At the moment that's only recent macs. This has a plethora of inputs as recited above, although you'll need displayport or Dual-Link DVI to take full advantage of the resolution. HDMI doesn't go that far. VGA would be such a waste of a monitor, though useful to have for emergencies I guess.
And finally, The display is to DIE for. Oh, and non-glossy, for those that are bothered by such things. (Wasn't a deal-breaker for me as I arrange my workspace accordingly anyway.) Some people have moaned about antiglare coating, but it all seems shiny to me, despite being non-glossy. ;-)