As someone who's had a GameTap subscription for a year or so now, I can tell you it's been well-worth my money, and I'd recommend it to anyone looking to get in on a huge game catalog for a relatively cheap price. Personally, I think services like GameTap and Steam are great for gaming, since they give independent developers a cheap and effective way to get widespread exposure. Episodic gaming has been gaining in popularity over the past few years, and I think we're going to see it increase as developers realize that it's a viable release platform. As for GameTap exclusives as a whole, I fail to see what's bad about the production of games that probably wouldn't get picked up by any traditional large-scale publisher. Besides good ol' Dr. Smart's latest project, GameTap's got the episodic American McGee's Grimm lined up for this year, the second season of Sam & Max is well underway, and they're funding my own personal stomping grounds, Myst Online. And that's not even counting some of the recent indie titles they've hosted. Sounds like good stuff to me.
As for the good Dr. Smart himself, I've been meaning to play Battlecruiser Millennium or Universal Combat on GameTap for a while now, just for the lulz, and I'll probably do the same thing for his new piece of drek.