I also like the SM-65 speakers a lot. Initially I bought just a pair for 2 channel music (no sub). I noticed that the sound loosened up and became smoother in the first few hours of operation. Later, when I bought 3 more to complete my home theater, I confirmed this by switching between new and old sets. The difference was apparent at first and disappeared after a few hours. The 5 of them are still in my home theater as fronts, center and surrounds and I like their smooth natural sound. So much, in fact, that I also bought a pair of SM-55 monitors for another room. That was a 3 years ago...
Now, after reading and researching for a while, I wonder if I made the right choice. The SM-65 speakers have a very impressive bass response that digs lower than seems possible from speakers their size. This is a good thing if you run them by themselves as a simple stereo set, but in the real world these would probably be paired with a subwoofer. In my case it's a couple of SB-13 Ultras. Now, all that bass extension is simply wasted because my SVS subs cover that range with much more precision and authority. So, I think that if you want bookshelf speakers and plan to run a subwoofer as well, it makes more sense to get the ones that concentrate on the mid-bass frequencies and higher, but do it extremely well. The extension below 60 Hz or so is not necessary.
I've got a pair of SVS Prime Bookshelves sitting on top of PC-2000 subs, and they sound amazing. You would never guess that these speaker can't dig all that deep.