I wanted the newest 4B-SST2 amp, so I bought it new.
I could have waited around to save money on a used BP-26 preamp, but i just bought it new along wht the amp, and the phono BP1.5
I just had the money and went for the package (along with the Magnepan 3.6 speakers bought all at the same time.)
I have purchased used items off Audiogon and been very happy.
So in general I buy new and used. I just happened to buy my Bryston together, new.