Honestly, they are pretty similar. Both make high end and low end models. And in both cases, you get what you pay for.

Budget machines of both brands tend to be very flimsy. I have seen everything from the keyboard to the power plug die with minimal abuse.

Their higher end machines are better. One note: as far as I know, HP is the only of the two that produces business-type laptops (the ProBook series). These are a bit more rugged and have more expansion options at the cost of greater size and weight.