Do you still use one in your system?
Nope. The one I auditioned was for just that; auditioning. After gathering opinions from me and others, Wayne did some modifications and is still (I believe) working on projects which incorporate some element of the Buffer.
It worked wonderfully in my system, and if I had known I'd never want the ability to add another source, I'd have ordered one one the spot. Truth is, I was waiting for Wayne to devise some sort of Buffer-based pre, but I don't think it ever materialized.
Incredible performance for the money. All the sonic benefits of the best, most neutral active preamps IMHO, sans the ancillary functions (additional inputs, HT bypass, etc.).
I doubt you'll miss having one, though. I've not suffered without a separate pre, and Dan's modifications will afford you an even better presentation than what I've lived with the past couple of years.
Besides, as my wife is fond of saying, "You can't miss what you don't know you don't have."