Not the person you asked, but I’m starting my 6th/7th courses in the OMSCS program this semester.

It can definitely be interesting, but like any program, it depends on the course and professor. I’ve had some great courses (like the intro AI course I took last Fall) and I’ve had a terrible course (decent relational database course, but the only TA who responded to questions was absolutely terrible to students).

I enrolled in the program because I don’t have an undergrad in CS. I wanted to strengthen my credentials and, more importantly, my foundations. So far, I’d say the program has definitely helped with that. It is also a lot of work, but one course a semester isn’t going to preclude you from having a life. Two will keep you seriously busy though.

It is very much dependent on what you want from it. You can take an easy curriculum and maybe the hardest class will be graduate algorithms. And that class sounds more daunting than it is. But if you are up for it, there are some great classes with great professors who will really make you earn it.

I just finished OMSCS last year. Did one course at a time, no breaks, found the workload for most courses to be quite manageable; i.e. if you're already a good dev and have decent writing skills, you'll probably only have to touch grad school stuff a few times a week if you know how to prioritize. For me, most courses were like 40%-60% interesting, the rest feeling like busy work or the typical kinds of overhead you get within any academic framework (I mean that less flippantly than it sounds; personally, it's the highest density of interesting content I've had in an educational setting). The program forced me to explore a few topics I probably wouldn't have otherwise, which is good...but I'm also the type that enjoys building and launching side projects, and I found it hard to do that in any meaningful way while working full time plus OMSCS. So looking back, I can't be sure yet if the piece of paper will have been worth the opportunity cost, but overall I thought it was a good program.

Some courses are trash: Computer Networks, Knowledge Based AI, Databases, System Design.

Others are amazing: Big Data for Health, AI, Compilers, Deep Learning, Operating Systems, Computer Architecture.

All in all, for the price (and the right classes) it's a steal. Another thing to note is that courses are mostly run by TAs - professor availability/involvement is rare.