I work full time as a systems engineer and have been a software engineer professionally for the last 3 years. I have a Bachelor's but it's not in anything remotely related to CS. Is it possible to be working full time and doing the OMSCS and succeed?
I'm half way through OMSCS while working a full time software job with an hour commute and a family with kids. It is doable but difficult. Large portions of my weekends are spent on homework and assignments. I find I spend about 20 hours a week on school. I haven't had to miss soccer matches or piano recitals but I've frequently skipped mowing the lawn or working out to finish assignments.
Yes, it is doable. I worked full time, and managed to take two classes my first semester, and a couple of other semesters I took one class and TAed another. Plan on having it take up all of our evenings and weekends. It won't always, but often will. For a couple of classes I even had to take some vacation days to finish up a project.
Yes, but it all depends on your ability and capability to strain yourself beyond normal, just for the short duration compare to the benefits in the long run.