I agree, I think the CB line gives you the best of both worlds. It's a forgiving iron with the blade-like look. From the address position, you wouldn't know if you're hitting the MB or CB, the top profile is very similar and for the average player, the cavity will help you a lot. With the MB line, you have to hit pretty solid shots, if you are one of those who regularly miss the sweet spot (like 95% of golfers), I'd suggest the AP1/2 or CB model.
For the player using the 735's I'd think the easiest transition would be to the CB/MB blend set. Much like the zb/zm blends you see on tour, just with the new 710 line.