I have to say that, of the three, I enjoyed Yangon the most. The fading colonial quarter was extraordinary, and I enjoyed witnessing the burgeoning middle class and a city in huge and rapid transition.
Inle might have been beautiful but it bucketed with rain while we were there this April.
Bagan was a disappointment. The fields of pagodas are extraordinary but there's not much there once you've seen the overview and inside one or two. The pollution is shocking with the sun completely blocked out for the entirety of our stay, and a trip on the river was frankly dull when you could barely make out the river banks.