Nothing wrong with driving those, but don't limit yourself. I drove Class B stuff for years and I know many people go to CDL-B many times because they think it's easier, which many times it's not. Remeber that scene in Austin Powers when he was going an inch at a time back and forth in the golf car because he couldn't turn ..... That's CDL-B Driving LOL!
Seriously though, I'm very upset it took me so long to upgrade to A. You can still drive B stuff, but you have options!