I've gone from classics to 2 Max on my track bike (my road bike has always had classics).
The improvement I noticed is that the engagement is much better, much more solid and I know when I'm in or out of the pedal (the classic always felt vague to me). Even more of a bonus when you consider this was for a track bike (fixed wheel). I felt like my cleat wasn't going anywhere, but the 'float' of the classics seemed odd to me and, both pedals were used with the exact same shoe and cleat.

I personally don't like the blades design, and nor does my trusty LBS. He said that he has sold four pairs (at the time I brought my 2 max pedals), and all four pairs had come back with broken 'blades'. I can see the appeal of weight loss, but that's all.