For what it's worth:
I have purchased 2 Q-See dvr systems from Costco. The last one, a QT528 developed a problem after a few months and would not boot. The Q-See web page directed me to a special RMA page for Costco customers, they get a little better warranty service and was also contacted by Costco customer service and given a contact to let them know if Q-See customer service does not take care of my problem to my satisfaction. The dvr needed to be returned, Q-see sent me a return label for UPS and less than 2 weeks later (not sure how long it was) I received what appeared to be a new dvr. Q-See paid for shipping both ways. Overall, I was very pleased with the customer service.
However, I am thinking now my next dvr will be a dahua ( or a brand made by dahua) because it is the only brand that has any type of software for linux (Linux PSS 4.04.2 works with kubuntu 12.04) . It works with my 4 channel Q-see but not the QT528, so I am considering a new 8 or 16 channel full D1 dahua dvr, just have not found the one I want, I also need to make sure it works with version 4.04.2 of the software because dahua does not intend to upgrade the linux software.
joe