From what I've read there's no real adapting needed to mix and match the frames and slides... you could well toss a SC slide/barrel onto a compact frame and go for it.
I have all three sizes in 9mm and conversion kits in full size for all the other calibers. IMO, the compact size just feels the best in my hand; it just seems to balance better than the full size while filling my hand better than the subcompact.
Shooting these things is indeed boring... just feed/shoot/extract one round after another, one shot after another, holes appearing in the target as they should...
There's folks out there who won't ever give it a chance and others who will never acclimate to the DAO trigger, but the bugs have been worked out and the P250 is a great platform.