Hello, I had the first pair of 2.7X delivered in the US. I got them in December. I have not compared directly to the 3.7i so I can't really comment on a comparison. The 3.7i were just too big for my room, I felt. I have a pair of VMPS subwoofers that I use with them, crossed over at 80 hz. The main differences between the two speakers is the size of the bass panel (3.7i is larger, more bass, which I don't need) and the 2.7X uses the 40 inch ribbon, rather than the 60 inch in the 3.7i. I was told the crossover point for the ribbon in the 2.7X was lower (more ribbon sound) than the crossover for the longer ribbon in the 3.7i. Both require a lot of current from your amp and large gauge speaker wire to handle that current. I invested in a pair of Odyssey Audio Kismet mono-blocks which fill the bill. I think the X upgrade is a significant upgrade, and would have major FOMO without it. Taken a little while to get get everything set up and sounding good, but am now a happy camper. If you have subs, or would use sub, I would suggest the 2.7X.