As said, incompatible.

If you're the type to play a game a few times and you're enjoying the game, I'd recommend your first playthrough as vanilla. And then youre 2nd as CoH.

Vanilla isn't a bad game, but... okay. It's a bad game. But it's still really good. :)

If you don't get a game-breaking bug, it's pretty fun. Keep multiple saves (that goes for CoH too) so if you do get a bad bug, you have some hope.

If you're not the type to play a game twice, then start over with CoH. :)

P.S. It won't feel like starting over. Lots changes.

"CoH"? So you're advising him to play this game once, then dump it for Company of Heroes? =)

Hahaha! Co8! I've been playing CoH almost every night for the past week and my brain exploded. :)