Well HP are overpriced and good luck getting Dell to fork out on their warranties.
I've had my Samsung for almost a year now, not a single problem and it's still under warranty. Around the same time my friend purchased an Acer and he hasn't had a single problem with his either. We're both heavy computer users by the way.
Bottom line: You'll find customer service complaints for every company, but you can't argue with value for money and build quality.
I seriously hope both of your computers hold up as going through their support and repairs will be painful
I have an Acer currently and it broke down 6 months in. Trying to get it sorted with their customer support was a mess, Had several issues with the unit(battery, OS, RAM and HDD) and they just fixed the RAM issue and said everything else is not covered by the warranty, which is a joke by any standards.
Enquireing with their support was also pointless because they just kept avoiding answering the questions I asked and gave some genereic lame answers which didn't apply for my computer.
As for Samsung, I'm refering to a friends experience who is a computer wiz and works in a repair center. They used to be Samsung's official repair center, but it was impossible for them to work. Samsung expected them to get everything sorted in 1, max 2 working days. However that did not work since Samsung never provided any spare parts to them unless a repair was logged and then it took them 1-2 weeks to actually ship those parts to get the repairs done.
EDIT - Oh and for HP to be overpriced.
I'd buy a HP any day because I had a HP Pavilion prior to the ACER and that served me for 5 years, before the HDD just decided it was time to go