One thing I forgot to mention, I purchased all my B&K used. I got a great deal on the amp, and I had my heart set on a B&K pre/pro. While looking for a pre/pro, the Ref 50 was available used for around $1000 and up. The Ref 30 was going for around $600-$800. I e-mailed B&K and they told me, IIRC, it was another $700 to upgrade to a Ref 31 (same guts as a Ref 50; no balanced outs). This was when B&K responded to e-mail inquiries. Why would anyone do the upgrade? You could sell the Ref 30, buy a Ref 50, and make money! I eventually found a nice used Ref 31 for about $850 and purchased it.
I've been very happy with the sound and performance of the B&K products, but after reading the above posts and thinking more about it, B&K has become a company filled with empty promises and poor upgrade choices for their user base. I'm no longer certain the Ref 70 is in my future. I'm going to seriously look at Arcam, Nad, and Rotel. Prices are similar, if not less, and, at least with Arcam, the sound will be as good. Maybe better?