Well, I just started my account with GameTap and so far, so good. The game selection screens leave a little to be desired, the games are displayed in an arc, which just doesn't look all that great, but other than that, it's smooth and slick. Download times are fairly fast, I put every episode of Sam and Max into my download queue, they average between 100 and 200MB, and the first episode was ready in about 10 minutes. You can only have one active download at a time though, which is kind of a bummer, but not a deal breaker for me.
They have a direct link from every game to a forum area supporting that game where you can go if you have problems with installing, or other bugs, they even have a link to any known issues with the games. The whole package is well presented.
There are some added benefits that I wasn't aware of when I jumped in. They have daily challenges and contests and such, some with prizes, some not. They have a forum that upon first glance seems to be rather mellow, I'm assuming that it is heavily moderated, but the community seems to be fairly chill. Some of their games are "Challenge" games, where you can play against other people online. If you're a fan of old fighters like Street Fighter (and many of it's incarnations) or Samurai Showdown, or King of Fighters, they have a great number of them in Challenge mode. There are some older atari era games, some bubble bobbles, and many more as well, I'm looking forward to some multiplayer fun.
Hey, another episode of Sam and Max is ready.
I'm more impressed with GameTap so far than my jaded heart thought I would be.