I like Dell because their 30" panels are high quality and you get a solid 3 year warranty. First 30 days, no questions for a brand new replacement, after that for the rest of the 3 years; no hassle RMA for a refurb replacement.
That being said, I've had mine for close to three years and have not run into any issues at all. It was nice for the warranty to be there though and I assume since I've made it three years, I'll likely make it quite a few more with my current panel.
If HP has the same level of service and warranty quality, it comes down to contrasting unique features of either model. You may not need the additional U3011 features/connectivity, but it doesn't hurt to have them. At the time I bought mine the 3008 was available, but I went 3007 for less input lag due to it not having any built in image processing/scaler/OSD.
I'd like a U3011, but I am so satisfied with my 30"er, I'm not upgrading it till it dies. 30" 1600P monitors are such a great investment, high quality IPS panel, largest resolution available and great durability equals hardly any need to ever upgrade. :thumbsup:
Bring on the 4K panels though. :awe: