I completed an MS in software engineering while I was working. I ultimately consider it to have been a waste of time and money. I think it gave my resume a slight boost early in my career but I don't think it matters much now.
Stuff like Project Management, Quality Control and even formal real-time system analysis are probably not concepts I would have learned on my own. Coming from an EE background, it definitely gave me a leg up. Not to mention the class discussions with people from widely varying software niches give really useful perspectives from outside your own little bubble.
While powerful and topics that need to be taught somewhere, that's not the takeaways I would've expected from a masters in computer science. I suppose we're talking about a masters of software engineering, which makes those topics feel more relevant. Perhaps that shows the importance of program selection and concentration.
TBH, I didn't intend to get a degree when I started. I took a couple of interesting courses, but then all the other ones that looked good (like real time systems analysis) had required prerequisites. Once you've taken those prerequisites, you might as well just take all the credits required for the degree.
Software Project Management was one of the required classes and it turned out to be one of the most interesting ones of all!