He's ok.
I never played kill puppies for satan
Dogs in the Vineyard had an interesting and novel mechanic that looked good on paper but I didn't feel like it played well on the table. I really dig the setting.
Apocalypse World is decent. I like the character sheets and simple 2d6 rolls and the fact that the GM never rolls dice. I think it could evolve into something really good. Sex moves are just edgy bullshit.
I appreciate his experiments and new ideas, I just don't think they always work. I can't even hold that against him. At least he's doing something new.
I also dig his super bare-bones settings. He gives just enough to give you an idea about what the game's world is without cataloging all the details. Two different groups could play DitV and be playing the religion completely differently. One group could be playing the dogs like paranoid burn-happy 40k witch hunters and another group could be playing them as mostly non-violent and not superstitious. For that matter, the same group could play two campaigns and play the religion totally different.
On a scale from 1-10, where 10 is Greg Stolze, I'd give Baker a 7.