Its at least two generations newer than your T2i. Some seem to think that the number of pixels defines a sensor generation. It doesn't. This is supposedly a second generation Hybrid sensor.
As far as IQ, at low ISO's you are almost certainly not going to notice any difference. Improvements to sensors are most noticible by the reduced noise at high ISP's, or, in this case, by better hybrid autofocus.
The bottom line is that its a improvement for focusing in the live mode, and probably has a bit lower noise at high ISO'sin jpeg mode due to the new Digic 5. Certainly no big difference unless you want autofocus while taking video.