A toothbar will dig out small trees ok. I have a BH as well but used the toothbar to dig out 30 or so 1-4" trees. Just get a tooth on/under it and curl the bucket to pop them out.
While you could dig out a sizeable tree with a toothbar I would not generally recomend it. If you just had one or two trees and thats your only resource then go for it. However it will be slow, messy and hard on the loader.
For general digging the toothbar will be noticeably better than a flat edge. You can also scoop/rake up brush/trash easier with much less dirt. Bottom line is that what your doing now will be easier with a toothbar. However I'd look into renting an excavator as the primary means of stump removal.
