I have a SP B1 and I would be remiss if I didn't recomend it. It brings out the midrange character in my voice better than any of the other mics I have. So many of the recent "vocal" mics tend to scoop out the mids too much IMO. That sounds really good when you just listen to them by themselves, but when you add them to the mix you loose the character. The B1 doesn't do that IMO. If the B3 sounds just like the B1 in cardioid then I would get the B3 for the added features. You won't be dissappointed.
Blessings, Terry