Bloodygoodgames: I own around 70 games on GamersGate and at least 50 percent don't work at all or I had major problems installing them. Needless to say, I haven't bought a game there in a year.
Many games on GG don't work correctly and, as a company, they don't give a toss once they have your money. In fact, there's no customer service to speak of as the replies you get take days and are almost always useless. Then it's up to you to find a fix on their forums -- IF someone on their forums knows how to fix it that is.
I currently have 4 games I bought from GG that won't play at all on either of my computers no matter what I try. At least 20 others gave me huge problems, and two of those would never have worked if someone on GOG hadn't given me a complicated fix that works.
GG has also now gone to just about 'Steam only, all of the time' and when I sent an email to their customer service asking why they were 'selling out' all I got back was something on the lines of "Shit happens" but more politely :)
I haven't bought anything on GG in a year and won't now. I'd also love to be able to get rid of the games I do own there and rebuy them on GOG or DotEmu but, once even attempted to download, you're stuck with them -- whether they work or not.
By the way, I used to be a HUGE GamersGate fan, even promoted them on my website and did free GamersGate giveaways. With all the problems I've had with their games and with their general We Don't Care About Our Customers As Long As We Get Your Money attitude, I wouldn't recommend them to anyone anymore. Sad as they once seemed like an extremely good viable option to GOG :(
I've never had any of those problems with Gamersgate for the most part (Company of Heroes didn't work though so I stopped buying games from them years ago after that when I then bought CoH from Steam and it worked just fine). In my experience they still seem pretty good with indies/smaller releases(I like the shmups and japanese games they get that never come to GOG).