I have followed Krell for at least a couple of decades and I can say a couple of things with certainty. You really don't know the full capability of your speaker's bass until a big Krell mono gets ahold of it. Krell's designs have never been the last word in finese but big-time into dynamics and control. It seems that there are always trade-offs.
Why Is Krell Not Considered Hifi?
No one seems to think that Krell sounds hifi, but just hifi price. They say it sounds hifi in that context that it doesn't sound real. I have to admit their products do have a metallic like cast to their tone, but aside from that I think that they are very smooth and detailed, far from the best in detail, like a CJ Premier preamp but they do make decent stuff. And just from looking at their products it makes you believe they sound as they look. Obviously its not true, but Krell makes decent stuff that has a good rep and is easy to resell (as long as its a current model, which is hard cuz they have so many new models) but its no way the sound of a Rotel or NAD that many people say.