Despite my clear skepticism about the product and hesitation to initiate discussion on Powercranks in this forum, I frequently wonder about this question and how others deal with it.
Let’s say you have one or more frequent training partners. You hook up for rides together or with a larger group a few times each week. Then you get a pair of PCs. Frank recommends using them full-time. What happens to you and your rides with training partners? Do you just go off on your own for your 10-minute baby steps during your adaption phase or do you keep up with your normal riding with partners while adding PC sessions on a trainer to try to adapt on your own?
This is an issue I might consider dealing with if PCs were priced half of what they currently sell for.
anyway, you have hit upon a valid topic. in my case, i had the things for a week and then had to go to madison wi to meet rich strauss and his partner/henchman/buddy and a fellow rookie tri-geek…i was to give them a guided tour of the MOO course at IM race speed. these boys are fast as all hell, and i am not bad at sucking wheel so we did ok but i would have been shelled instantly on my new PC’s. so, i switched them back and had a fine day. then, i put the PC’s back on and returned home. once here i left them on and never regretted it once. i did not ride with the fella’s - but in truth i’ve been riding with these guys for 17 years and i needed a change anyway. 
our local group[ ride is like a race, and there was no way i could stay in the small, inches apart, aggresive and attacking ride with them at the time. the handling issues were as much of it as the pedalling, i think. this coming year, tho, i think this would be different. i have the handling issues sorted and can now sprint and recover and generally motor as i wish on them i believe. ( it’s winter here so i am not sure). in any case, the feedback i receive riding the things is/was worth it to me. but, a fella has to be willing to kinda trust the process and be patient. your buddies will drop you right off and if that is unlivable to you don’t bother. in my case i am 42 y/o and having been riding for many years and iif i was gonna get better doing what i was it would have happened by now - this, plus the immediate positive feedback i got from the PC’s - the feeling that this is how one should be pedalling a bicycle was more than enough to send me happily out PC-ing on my own. within 6 or 7 weeks or so i was running faster than my 1/2 IM race speed for 1.5 times the distance at the same HR. . . .and riding 1.5 times the 1/2 IM distance at the same speed as my race pace with a HR 12-15 BPM lower. i am certain, looking back many years, that 6 more “tuesday nite fights” would not have done that for me. hope this helps.