Hey! First of all a massive congrats on getting into all these programs. It's not easy - so that's terrific!
Here's my thoughts on the schools that could help you out a little bit (and hopefully future students who apply) -
1. Harvard MDE - Obviously has a small cohort size (like all the programs) and a focus on design and engineering. The tools and labs that they have are world-class (3D printing, etc). They have some pretty kick-ass electives as well that you can take at the engineering school from informal robotics to thermodynamics and so on. In terms of healthcare, you could also work in the Wyss Institute which constantly innovates. I think the only thing to keep in mind is that the possible focus on business will be a little bit more limited versus the other programs and that it is a fairly new program so finding that job after will require hustle (I think they do have someone who helps with finding jobs).
2. MIT IDM - Personally, really like their focus on looking for the right people and fit. Again, a very new program so what I've heard is that the basic 101 foundation courses in design, engineering and business can feel a bit boring if you already have solid knowledge in that field. The possibility of taking many other classes in the different MIT schools is exciting and I think you can take more electives here vs Harvard (not a 100% sure) which gives you more room to explore courses in MIT Sloan, Engineering School, Comp Sci and so on. Apart from that I think the MIT labs are fantastic - Media Lab (World famous for Innovation) and they have many others too. Plus, you could apply to MIT Sloan as well and do a dual degree. Again, since it is a fairly new program, not sure about that alumni connection, and finding that job will require hustle (They too have a career rep who helps you find what you are looking for).
3. CMU MIIPS - One of the oldest programs in the space, used to be called a Master's in Product Design (i think the name changed in 2013 or 2014). One thing that really attracts me to the program is the fact that it is so established and hence, you know everything will be streamlined and there won't be any sort of "experimentation" in a way. They also have a really strong network of alumni so connecting to them could be easier to find an internship and final job (that being said there is no sort of recruitment, so again requiring that hustle). I really like their Capstone project focus where you work with a company on a real world problem, similar to the Northwestern MMM program. The 1.5 year or 9 month program could be a positive or a drawback, however you choose to look at it. Drawback if you're looking to stay in school for a while and want to explore a lot, then 9 months or 1.5 year could feel short. However, if you're looking to get some more expertise, up skill and pivot or try something new the shorter duration could be useful to getting that job quickly (spoke to some alums - it's very well known in Silicon Valley). Unlike the other 2 programs, they do take students with very little to no work experience though. Not sure why you would overlook this school?
Berkley MDes - I don't know much about the school, but when I was looking into it, it seemed very environmental focused. Again, haven't done thorough research into this school, so don't know.
Look, you can't go "wrong" with any of these schools. They are all top top choices and are well known schools.
I hope this helps!