This is my first day with Yeti/510, and from what I understand, I got the redesigned model that should prevent leaks and has the manual switch. So far I am extremely happy with it mainly because of the consistent huge hit it produces. Far better than any 901 or 801 I've tried!
Don't know about the battery life yet, but my first day the battery lasted about the same or maybe a bit less than 901 battery. Recharge, however, seems to be faster.
One thing I don't like is the mouth piece -- I like the tapered 901 mouth piece much more. But I am sure manufacturer could introduce that in the future.
The atomizer does get a bit hot, but from what I can tell it is only when it starts running dry.
I'll need to see how well will the Yeti hold up with more use, but the throat hit is so spectacular with any liquid I've tried that this may become my favorite just because of that.