There are Avid BB7 road disc brakes and Avid BB7 MTB disc brakes. If you look at the red and white label on the caliper, it will say ROAD or MTB. I have experimented with using one of the road calipers with V-brake levers and it did not work very well. I have not tried an MTB caliper with a road bike lever.
If you use the appropriate caliper and lever together as recommended by Avid, they work very well indeed.