Thanks dangle I really appreciate the detailed feedback.
Regarding the saddle, it's not that I move around very little on the trainer and thus have problems, it's that the bike is rigidly fixed so neither the bike nor the saddle moves while riding. I find my saddle very comfortable on the road and I've done 6hr rides without a problem. However on the trainer, no saddle is as comfortable for me, and this appears to be a common complaint. I expect that since the bike moves a little as you pedal on rollers, similar to outside, that this will be less of an issue. Got it. I'm pretty locked in on the ol' Powerbeam and still find that I get uncomfortable easier on the rollers. That could be unique.

When I say "significant benefit" I'm really just asking if you feel the rollers make worthwhile differences to the outcome of your training above what you would get from just a trainer. From much of what I've read, the suggestion is that rollers promote smooth pedalling as opposed to the pedal mashing that trainers can facilitate if you're not paying attention.
I expect, regardless of whether I get rollers, I'll continue to do FTP and VO2 efforts primarily on the trainer. I see what you're saying. I think you're looking at it the right way too. I guess my thought is there really isn't evidence that mashing vs. 'smooth' pedaling makes you faster. You can train for smooth by working on higher cadence as opposed to hanging out on the rollers. Rollers will do it too though.


The e-motion was what I tried and I was really impressed until I saw the price. It's probably worth that price tag, but I would buy a Magnus with that money and replace the KK well before I would look at e-motion rollers. The fun thing is, you get to do whatever the heck you want with your money and I think you're looking at your options from a very logical perspective.