I use the Bel Canto 300 integrated amp (primarily with Sonus Faber Cremonas) and would observe that the amp is clean, powerful, and otherwise unremarkable. I have observed no real issues with the treble, but I've definitely heard more "texture" out of these speakers as well as better imaging. However, the better performance came in a different room, so I can hardly pin these issues on the amp with any confidence. If you need high output at reasonable cost and your speakers do not present an exotic load, I suspect that switching amps are a good solution. If you have more funds on hand, don't need the power, or have quirky speakers - proceed with some caution.
Marty
Marty