I think I need to leave this thread before it drives me crazy.
Distorted guitars can sound good on any size speakers (including ear buds or a laptop). Are they going to sound like a 4x12 cranked?.... probably not.
The Kemper is really incredible at reproducing the sound and feel of any amp as played in the studio. That being said, it's also great at outputting studio sound to full range PA monitors for live use. I'm not sure how it would compare to a real amp through guitar speakers unless you were using direct profiles; I've never personally used it that way...but it seems that a requirement for accuracy would be a direct profile that eliminates differences in mics, mic preamps, and speakers.
Good tone is good tone, regardless of the playback. It's completely amateurish and unrealistic to expect the bone shaking crunch or ear piercing transients that you might get when sitting directly in front of a tube amp, after it's gone through a mic, mic preamp, been converted to digital and recorded, converted back to analog, amplified, and played back through speakers of varying sizes and quality.
I've got a room full of tube amps that rivals the showroom at most music stores, and with a good profile I could replace any one of them with the Kemper and get professional results in the recording studio or live. I mean, sheeeeeeeesh, don't even get me started on the frustrations of live sound reproduction in any venue larger than a small club. I don't care what boutique tube amp you have...it can (and likely will) be reduced to sounding like a shrill solid state pile of junk after the talentless soundman puts a misplaced junk mic in front of it and applies EQ and effects to it. The Kemper can at least help by eliminating a few of those variables.
If you're not happy with the Kemper, fair enough! If I was sitting in my bedroom jamming out during business hours, I'd probably pick a "real" amp over the Kemper myself. For any professional application (recording/live/low volume rehearsal) however, the Kemper has multiple advantages, with few if any disadvantages.
Just my opinion....signing out!