It's interesting you mention that because a coworker and I had this very discussion a moment ago whether we can really consider all this rental development "a boom" As far as larger notable buildings which we focus on here, it's been constant actually. U of M has wrapped up their decade of construction which added millions of square feet. Here's the full list:
Private projects have kind of come one after the other. As far back as I knew much about Ann Arbor, it started with Ashley Mews in the (late 90's?). When I arrived at U of M in 2003, I recall the midrise above Buffalo Wild Wings wrapping up construction. Then there was Ashley Terrace, then 411 lofts, then that Courtyards development on North Campus, followed by the Zaragon Projects.
Basically since the early 2000's there's always been at least two larger buildings under construction.
I've visited nearly all the big Ten University Cities in recent years, and the pace of construction seems to be the same. University towns are doing well because of their unique micro-economies and increased enrollment which drives up demand for better student housing.
Going back to the original question, here in Chicago we've had at least a half dozen skyscraper starts every year since the start of the recession. That's slightly less than skyscraper starts during the mid 2000's when developers were building like crazy, but most of the boom consisted of midrise, lowrise, and single family homes. Seems like rental towers are all we are getting. Definitely skyline changers, but not really a "boom." But back in Michigan it's the same story.....I think Ann Arbor is getting by on a few of these nice projects, but I think construction still needs to pick up.