I've not read all 100+ pages of the Hard|Forum yet, but it seems the ZR24w has the advantage of sRGB and perhaps less dodgy panels than, say, the Dell U2410 (fewer shortcomings in tinting and uniformity). Depending on where you live and shop, HP service might be superior to Dell's, especially when it comes to replacement.
The main weakness of the ZR24w is the black level. IPS panels are never going to get as dark as PVA (let alone plasma), but out of the box the ZR24w is blinding. Even setting the brightness down to 0 isn't sufficient in some cases to get the black levels and contrast to satisfactory levels. Users often have to bring down the RGB levels as well, though you should have proper calibration tools if you're going to do this. TFT Central was able to get an acceptable black level for the ZR24w after bringing down brightness and increasing contrast to 100, then calibrating.
My present brightness is set to 5. So far, I don't notice any dead pixels or uniformity issues (touch wood). I haven't spent too much time judging the black levels on my display, but I'm used to IPS (have a Dell 2209WA and an iMac). At the other extreme, the telly here is a Pioneer plasma, so any LCD is going to fall short in regard to blacks when watching movies, etc.
Of course, I paid only $300 for my display, so if it's not as superb a monitor as an NEC LCD2490WUXi, I won't count it a great tragedy.