Dell has vastly changed within the past year or two, maybe three. I'd go down to best buy and check out the laptops in person, thats what I usually recommend to people. The Studio line by Dell Laptops really is pretty amazing. They're a lot more rugged and well built than most everything else on the market. Definitely check them out, they're worth the time and effort. The only problem is that they aren't cheap cheap, they start at like $600-$700 or something like that so most people I know get turned off right away since they want the cheapest option possible, usually around $400 or less. Pff. Whatev I guess, can't really blame them with money being so tight.
I actually like HP by the way. They're quality has been above average for a little while now, with Asus being in the lead I believe. At least, as far as returned products go. I think HP is somewhere in the middle along with Dell. Then again, they do say that most returned products actually work just fine. Something about people not getting what they were expecting or couldn't actually afford it or something like that. Buyers remorse is what they call it I believe, accounts for... 20ish percent or something like that of returns.
Anyways, another thing about the Studio's is that they are pretty customizable as well. You can get a 1080p screen for an extra $50 and a backlit keyboard for another $25. Among other things. Pretty nice imo. They also get up to 8 hours of battery life apparently, at least thats what they list.
By the way, a comparable laptop to that HP would be about $800, which is the list price of the HP. You get 500GB instead of 320GB, but you take a hit in the GPU department with 4570 instead of 4650. As to which I would pick... thats tough. I'd go with either one honestly. I'd probably end up with the Dell if I had the extra cash, just for the backlit keyboard and 1080p screen.
In short: The HP is better and cheaper in my opinion, but the Dell is pretty close and with nice customization options and great build quality.