I upgraded to the T4i from a T3i. I was optimistic given the reviews, and after a few days of use am happy with the decision. Basically, Canon bred the T3i with the 60D, threw in some brand new features, and the result is a very powerful camera. The sensor has been updated to permit continuous autofocus during video. I don't have an STM lens yet, but it works just fine with my 24-105mm L. Although I rarely shoot in Live View, the ability to pick your focus point by touching the screen is great. The touchscreen is very responsive and very helpful for changing settings quickly. The T4i picks up the shutter mechanism and autofocus points from the 60D. Five fps is noticably faster than 3.7 in the T3i, and with a UHS-1 card I am getting 7-8 shots per burst in RAW. The new Digic 5 processor seems to add a lot, it has 6x the processing power as the Digic 4 chip. My low light sunset pictures have much less noise, the clarity is amazing. Best of all, all of my T3i accessories work with the T4i. My Canon battery grip and remote and wired shutter releases carry right over. I've seen some reviews online that claim the improvements over the T3i are slight, but I disagree. While outward appearances are almost identical, the guts of this camera have been significantly upgraded on all fronts. Good job, Canon!