I had the opportunity to ride the 2011 Apex in 3 different configurations yesterday. To say the conditions were "less than ideal" would be an overstatement, but we got to evaluate them anyway.
Of course the biggest issue with the new Apex is the EPS........electronic power steering. Surprisingly you don't even notice it's there until you've just blown through a completely bare corner and not had to fight the bars one iota and then it registers on your brain......"SWEET". No twitchiness, no wandering, decent tactile feedback, but very little effort. Where has this been all my riding life?<g>
The new Apex also has all new skis. Without a doubt the best effort ever by Yamaha. Even in the nasty conditions they went exactly where pointed and seemed to hold a line extremely well. The SE happened to have Woodys Dooleys on it and was the best of the bunch with regard too steering.
The new motor is not all that more powerful than the 2010 model but the power seems even more linear if that is even possible. It just keeps on pulling right up until you let off, which because of the conditions was far less than the true top speed.
I was on the XTX first. It was set up extremely firm even for a guy my size (XXL) but handled very well, even through the chop and slop. I would want to do some adjustment though to soften it just a tad. I understand that later in the day some others did that and improved it immensely. Because of the combination of tipped up rails and the EPS you don't even notice it's a long track.
Then I rode a "standard" Apex. With the monoshock rear skid the ride was a little smoother than the XTX but that's expected since they are really aimed at different audiences. But it's an Apex. Everybody pretty much knows what to expect there other than the EPS.
And finally I got about 20 + miles on the SE. Some twisties, some straights, lots of rough, bare corners, water puddles, etc. etc. This sled did not care one iota what you threw at it it went where aimed and pretty much railed where it went even over bare corners. With the Fox Mega-Float as the monoshock this might probably be even better than the long proverbial M10. The only comment I could make when we were done was that the SE was the easiest sled to ride very, very quickly that this particular heavyweight has ever been astride.