I can say that the blades on the new SU trimmer are sharp! (I cut myself by accident, oops!) And I know when I tried it at convention, I tried it on Saturday afternoon and they said they had had the trimmer out since Wednesday and hadn't changed out the blade and had been demo'ing it pretty much non-stop since then. The blade still cut great, so that was a good sign to me. I talked to the gal who was in charge of the design of the trimmer and she said that the blades were a big thing they worked on when designing the trimmer. I seem to remember her saying they used a different metal when making the blades so they would hold up longer and they are supposed to have a 2-3x cutting life than they old "orange" blades. Obviously I haven't had my trimmer long enough to test that claim, but that is what I was told.
I DO know that the blades DO NOT fall out like my orange ones used to. In fact, in my video about the trimmer, I flipped open the track pretty hard and tried shaking the blade off and it stuck fast. If anything, I think it will be hard to get the blades off (though they go on really easy).