Short review: It was a pretty good movie, and Steve Carell was a good casting decision, but I still miss Don Adams. If you see one action nostalgia this Summer, see Get Smart. If you see two, see Get Smart twice. If you need three, there's Indiana Jones.
I guess my largest quibble with Get Smart is that they did a substantial overhaul of the Agent 99 character, but then they undermined all of that by gradually reverting back to the classical Agent 99. By the end of the movie, she's there just to hold the dog and dotingly say "oh, Max" whenever Carell does stupid things. I know that they did it for the nostalgia value, but they sort of treated their modernized, willful Agent 99 as a loose end to be tied up.
And speaking of tying... a silk necktie? Hands tied in front? As a Mission Control agent, she should've been out of that in under 30 seconds. Tug on that with your teeth! It's not hard! You don't need a knife for that! Bah. It totally isn't even possible to do that to a non-cooperating party unassisted while being pursued.