Which sport boots are "best" is totally subjective and based on personal opinion/preferance, as you can see by the variety of answers you have already gotten.
As for myself, I have used the SMB combo boots, the SMB II boots, and the new SMB 3 boots.
And I love the SMB 3 boots! They fit really well and I have found they let minimal dirt/sand into the boot, compared to the other SMB boots I have tried.
I probably will never buy combo boots again only because the bell boots wear out faster than the actual boot does. But then again, they are nice because the bell boot never turns because it is attached.
Just know that whatever boot you do decide to go with, DO spend some nice $$$ on them. Yes, they will be expensive but if you take care of the boots they will last you a very long time. I've had the SMB II boots for about 7 years and they are still in great working condition, but I take really good care of my stuff.
∞•*˚ Βгįťţαňγ ˚*•∞
It is not enough to know how to ride; one must know how to fall.