One of my regrets in things audio (and we all have them)is selling my KSA-50 II amp. This was a brash, kick ass & take names no apology amp that worked great with my Apogees. But alas, being an audiophile, I sold it for another amp. Big mistake. I've owned a KST-100 (didn't like)and a KSA-150 (nice, but a little....uninvolving).
I've heard from ears that I trust that the KSA-300S is a good amp. However, that "little" old KSA-50 was engaging as all get out and had that toe tapping swing.
My current amps are the keepers and are made by Reference Line (Silver Signatures with the high current, outboard power supplies). They have the grace and bloom of a good tube amp, the grip of the best solid state and the swing of the KSA-50. Hard to find, expensive, expensive to run (each amp is rated at 100 watts, 8 ohms and is class A biased all the way to clipping into 2 ohms) but they are worth it. I find that the solid state stuff that is HEAVILY biased into class A sounds the best, especially at low levels and with a glass of 18 year old single malt scotch.
To make a long story even longer, Krell HAS made some great sounding amps. You just have to pick and choose and don't be afraid to look BACK into their model line. Good luck in your search and choice.