I owned a Model 10 about 15 years ago, very nice amp as I recall. Slightly rolled off up top, stong, punchy bass and warm midrange. $850 seems like a good price, though to be honest, if I were looking for an amp in this price range I'd look for a Forte 4a. Granted it's only half the power of the Model 10 (50 wpc vs. 100 wpc). If you don't need the power, the Forte sounds better, IMHO, and will cost you less.
Cheers,
John