IMO, I think its going to really depend on your budget.

I bought a decent one a few years ago ( its an Inova ) that reads engine, trans, abs and SRS codes. I think it was right about $350.

Just recently found myself needing something that does A604 based electronic trans CVI cks and quick learns . So I just ordered the slide in cartridges to update my old stand by SnapOn MT2500 scanner. I've been buying cars with trans issues , and spending $100 at a crack for my local dealer to quicklearn it after I get it overhauled isnt cost effective.
They should be here in a few days and have my fingers crossed they do what I need them to do.