I was told by a gunsmith (who loves the 10mm) and read in some articles, that the vast amount of 10mm ammo sold is really just a bit more powerful than the 40 (kind of like 40p++). To get the real max power that the 10mm was intended for (some call it the true FBI loads that they tested with), it was mentioned to get 10mm ammo made by places like DoubleTap, Buffulo Bore, etc. Some of their top loads are said to be about the equivalent of a 41 magnum round (and I've read you can get the 10mm load up to 44 mag levels if you hand load).
Did you find that the commonly sold 10mm ammo was that much more powerful than the 40 you now carry? I shot both a common 10mm brand ammo (I currently forget the maker), and some of the more potent Buffulo Bore rounds in my Glock G40 and could definatly feel the difference in power/recoil between them. I'd be curious on your take on why you went back to the 40 (not that I'm saying you were wrong in your decision)