I have a masters and I think it was a complete waste of time and money. It has not helped me at all at work nor with salary.
I considered myself "technically competent" before and thought I could learn everything where it comes up, but past a certain level there are aspects to development that just are just really hard to absorb if you don't have the (hard, gritty) theoretical and mathematical foundation.
If you want to go towards the business and/or management side of things an MBA might make sense. But for a developer an MBA would be very strange on a CV.