I'm entering the HEMA program at Kellogg. I can't give first hand knowledge since school hasn't started yet, but from what I've picked up from current students and faculty, it's a relatively small program at Kellogg (I think about 50 students a year pick the HEMA concentration, but the school is interested in growing that to about 75), but with a very strong and involved alumni network in just about any healthcare-related career path you'd be interested in.
During DAK, someone asked how Kellogg compared to other top programs. The answer was that Kellogg, along with Wharton and Duke, are considered to be the top 3 healthcare MBA programs, but they all take a slightly different approach. Kellogg's is probably the most well integrated with the rest of the MBA curriculum, and has very strong faculty and other resources. Wharton's program is the largest and has great professors and resources, but is a bit more of a standalone program. Duke's program is very closely aligned with the university's hospital and medical school, but otherwise didn't have as many resources as Kellogg or Wharton and focused a bit less on the business of healthcare than them.
In the end, if you're interested in healthcare you're going to be in great shape with an MBA from any of those three schools. For me, I didn't apply to Wharton because I just didn't like many aspects of the school in general and didn't think I'd be happy there. I ended up deciding between Kellogg and Duke and ultimately the deciding factors were not really related to the healthcare program specifically, but were more general considerations about the 2 schools.