Ok, I'm not sure I got the correct HP, because hardware wise acer is far better than HP, I don't know why they would be priced the same...
as far as reliability, my personal opinion, both HP and Acer are crap.
if you want reliability, get the best possible warranty with max duration, that way if anything goes wrong they replace it at no cost to you. if nothing goes wrong, you'll get at least 3 good years out of that laptop.