The RX-V2600 was a marketing tool; it had significantly higher performance/quality to the prior (RX-V250o) and future (RX-V2700 and later) models. This was apparently due to it being the 1st in a new major revision of receivers from all manufacturers that year. The pre-amp is 1st rate and it's a very nice looking unit for a 2 channel set up, with it's nice solid metal front, with simple design (only a couple of knobs and buttons visible, most controls hidden behind an access door). It has superb measured distortion performance, great SNR (dead quiet, even in an extreme low noisefloor environment), flat response and superb line level operation voltage ranges (input/output up to 4 VRMS without clipping/problems). Every subsystem (preamp, amp, video, etc.) operates from its own isolated power supply system, also, with many multiple taps coming form the very substantial main transformer.
I use this exclusively as my main 2 channel pre-amp. Note: you do need to hook a small monitor up to it to do initial setup/configuration(s).
-Chris