One thing to remember when asking opinions on computers, is that everyone has their own experience. My husband and I have owned a Compaq, a Dell, Gateway and two HP laptops. Our desktops have been Gateways, HP and Dell.
This is what we've found. For desktops, Dell seems to have an edge on the rest, although the latest HP desktop we bought for one of our sons (got a good deal on it) has worked great. Our first HP desktop was a lemon.
For laptops, HP seems to be winning out as far as usage and durability. In fact, we just bought our second HP laptop because we were so pleased with my husband's last laptop (an HP). The compaq broke pretty quick. The Gateway had a power cord issue straight off but had great CS that sent out a new one. But then the hinges failed just after about a year. Then the power button. And it all started to go downhill. My husband's dell had the same issue with hinges but he ordered parts and repaired it. However it started to break again pretty soon after and parts were hard to find and it didn't run well.
The HP laptops really hold up. My husband has had his for two years and nothing has broke yet. It still runs pretty well, and he hasn't done much in the way of maintenance on it. I got mine for mother's day and love it. It was $700, we did not buy the warranty because my husband's career is computers. If it's fixable, he can do it. But there are other models that cost less if you need to buy the warranty.
Samsung models have some good units, if I remember from the research I did earlier. There was one model in particular I was going to buy but they were sold out and no longer offering it online. I'd shop online and read reviews. Wish I could help you more but I don't have any experience with samsung.