As I own both the 3.7s and the 2.7s, I agree. The 2.7s do sound slightly different, the 3.7s sounding more open and a bit more resolving of the finest details and "air" around voices and instruments.
The 2.7s are pretty darned good, though. In a way I find the tonality of the 2.7s a little bit more beautiful and rich. But as I say, it does seem at the cost of the last bit of openness :-)