I'm a big steam fan, I own many games of Valve's hand, and I enjoy most of the games I've bought through sales and discounts, games I'd otherwise not had.
DRM crops up, but basically any game has that, but we choose to ignore it. Steam is one of the few producers who can actually enforce said policies. Besides, if you're going to cheat, scam duplicate or break the rules, punishment is sure to follow in the real world too.
It's the argument a friend of mine has too, because she swindles people out of their stuff just by being a girl (that's not exaggerating, she's got mad skills doing that), people will complain, and she'd lose her account after the 9th billionth occurrence. She doesn't actually steal it, people just give her stuff, and passwords, and more stuff. it's a recipe for disaster. Steam doesn't allow her to do that, so she won't use it (missing out on so many good things like sales and such)
ahem, back on point. I love steam, they make buying games easy, they make good games( with regular extra FREE content) and they are helpful if you have a problem with something. for instance, I bought l4d2 in the store, but the code didn't work. then they fixed that fast and friendly.
and yes, sometimes it's down, but I usually only play online games on steam, and if I haven't got internet, that's hardly Valve's fault. I'll just play any other game in my MASSIVE list.