...so I will post the same answer: For me it was useless.
I did my Masters (in Engineering, not Comp Sci, but my example might still be relevant) and discovered that, although I enjoyed the program, as far as my career was concerned a Masters degree was worse than useless.
After I graduated I was hired at a starting salary. My Masters' experience counted for nothing. I was therefore making less money and had less seniority than my former Bachelor's classmates, and was essentially doing the same work. When I was looking for a job, some employers were openly suspicious of my intentions, saying that since I had a Masters degree I would probably quit after a couple of years and go seek a Phd (so why hire me?).
Would I do it all again? YES! Because I really enjoyed doing my Masters and was very very interested in the research that I did. That is the most important thing. If you don't love the subject, you will hate doing your Masters.
I know many people who have done Masters degrees, and the only ones who benefited career-wise were those who continued on to their Phd and those who did MBAs.