I've owned the Classe CAP-151 integrated, the Bel Canto s300, and am currently listening to the Bel Canto eVo2i. The Classe came across as dull and lifeless (boring) compared to the eVo2i. The soundstage is much deeper and three dimensional with the Bel Canto. As for the s300, I would agree with Gmood1 that it is neutral, exceedingly so. The s300 was used without a preamp so not sure how relevant my assessment is.
No experience with Classe power amps but the eVo2i has the same amp as the eVo2 you asked about.