halocline
Contributor
Let us know how you like the B2 .
I wish there were some kind of "try before you buy" program - it might take some of the mystery out of an expensive purchase. Then again, I suspect the B2, Mk25/S600, or Legend LX would be so much better than the rental regulators I've used that I might not be able to tell them apart.
You probably wouldn't be able to tell much difference between any decent quality regulator that's in good working order and tuned correctly. Certainly all of them perform adequately.
In terms of minimizing risk on an expensive regulator purchase, that's easy. Buy a less expensive regulator and continue to enjoy diving. I use regulators in caves that cost me less than $150, and that's for two sets. (MK10s, D300, 109)
Regs have not significantly improved in a few decades and there are excellent deals to be had on used regulators. The dive gear industry has done an excellent job of hyping regulators (aka 'life support') so that unsuspecting divers shell out a LOT of money for very simple devices that have a pretty easy job; reducing the pressure in the tank to ambient pressure on demand.