Lenny, the 200 is a 15 inch speaker. I can't speak for church gigs, but mine served me very well during jam sessions. It was just loud enough to play with a drummer, and Rumbles have a nice vintage tone and take pedals well.
I can't say if the 100 would be loud enough to make it over a drummer, but it would probably be pretty close depending on how heavy handed they were and if you had PA support.
The 200 also has a nicer speaker in it and will let you hook up an extension cab.
I liked my Rumble combo enough that I picked up a Rumble cab when it came time to upgrade.