...sometimes I wonder just how well the PM1s can handle a good old-fashioned rock song. ;)There's really only one way to find that out: a live audition; no description can do it for you. Even with rock, different people are looking for different levels of volume, and that volume is contained by the size of your listening venue.
There is also the issue of whether you include a good sub (PV1D recommended, especially to rock out or for large-scale orchestral music) or not. In an 11x13 room the PM1 would probably rock out fine, but would be helped by a sub. For most people the PM1 + PV1D in an 18 x 22 room would be just fine, too, though some might want it to play louder without compression.
Although I consider the PM1 a more advanced and refined transducer than the OMD-15, I have to say, I am still amazed at how good my OMD-15s are. In the last couple of days I've played some well recorded LPs of Frank Sinatra, Boz Scaggs, and Kenny Rankin singing standards from the "Great American Songbook", backed by an orchestra, and the results through the OMD-15s are captivating. I've had these speakers for five years; two years ago I added a pair of Mirage MM8 subwoofers and that will probably satisfy any upgrade fever for some time to come.