Never upgrade, no warranty, software additions removes Tech Support. One bad year will bankrupt most of these manufacturers. The third largest computer distributor in the world when bankrupt about 8 years ago. I have seen lots more distributors and manufacturers go under since. Many older major computer companies and system manufacturers have or are leaving the business.
Quality is fair overall.
Some have technical support 24 hours a day. Wide variety of computer parts inside. Seldom can you state exactly what you want inside and get it. One of my customers, whose network we maintain, bought the best Dell computer they make. A couple of things they ordered was wrong.