I don't get up to Museum Mile that often anymore, but I recently did make it all the way up to 5th and 103rd to check out the "New York Comes Back: Mayor Ed Koch and the City" exhibition at the Museum of the City of New York. I love mayors, their frazzled mania, the way their craziness is an indicator of where their city's at, their mythos in general. So I thought the parts of the exhibit having to do with Koch The Man were fascinating (he had a Trump-like penchant for immediately firing any staffer who wasn't cutting muster, and he fired many), while the urban-redevelopment propaganda was a little more suspect. I checked the website later on, and sure enough one of the major contributors to "New York Comes Back" was Forest City Ratner (and Bloomberg as well, but that's a no-brainer).
I recommend "New York Comes Back" if you're into what I'm into -- but please take it with a grain of salt, and remember that it's being paid for with a lot more than museumgoers' $7-a-head suggested donations.