I also did both on an M3 cabrio delivery this year and a) DID find the wait for the car to come back to be interminable (making it a PCD actually made it worse by almost 3 weeks (compared to if I had paid for a delivery in NYC), in my case.)
And, b) personally speaking, see no comparison whatsoever. Euro delivery was just one of the best 2 week spans of my life-- incredible, incredible adventure. PCD was very fun and educational, but not even in the same league as the life-changing experience ED was, IMHO. Nothing prepared me for how incredible euro delivery was-- and I did it in winter, eliminating a lot of places and flexibility-- had to return in MUC-- never would have done so if I didn't need to, far too limiting and boring driving back to MUC on the last day.
I'll never buy another car without doing it via ED, but I wouldn't bother doing PCD again-- fun as it was. Although I'm definitely going to do a M-school there very soon-- which, actually, is what I'd recommend to you.
Plus, you can do the Tail of the Dragon, etc pretty much anytime, living relatively nearby, so, IMHO, that makes PCD even a small notch less appealing as an "experience." same cannot be said of all the unforgettable driving one gets to do in Bavaria, Austria, Italy, etc