I was fortunate enough to be able to try a few graduate programs before eventually going with Boston University.
Because I had at the time, the GI bill the military would pay for almost 100% of the tuition so just "trying out" schools was not much of a financial risk. Two schools I looked at was the University of Phoenix and UMUC graduate programs. I first started with UMUC simply because I went there as an undergrad so I was already familiar with the program. I enrolled in two classes at UMUC, which in hindsight was not a good idea. There was simply too much work to do. The class work is very challenging, and there is often a ton of reading assignments. I would add that it's a very good program, and you have a lot of direct contact with the professors. In fact, I don't recall there even being a facilitator/graduate assistant role. Now this was about 10 years ago so things have likely changed. Additional, the technology was a bit clunky and non-intuitive, but once again, this was over 10 years ago so factor that in by today's technology standards.
The Phoenix program was too easy in my opinion. Again, let me add that I attend their program about 9 years ago so things might have changed. First of all, there we no "real professor", no tests, and almost all of the books were Phoenix supplied material. Factoring in that I was in a graduate program, I was looking for more of a challenge than want Phoenix could provide. Currently, there are still quite a few complaints about this problem. Moreover, I'm sure there are some fine students graduating out of the Phoenix program. Unfortunately, the problem I had was that other students did not seemed prepared (particularly by graduate school standards), which effectively impacted the level of discussion, and the quality of team projects.
After taking a break from pursing a MS, I would return almost eight years later to purse an M.S.in Project Management. I looked at a bunch of schools and eventually settled on BU. I found that the BU program and its reputation was the best of the online schools. In fact, I found the campus reputation to be very good which made my decision to choose BU much easier. I would learn that it's best to attend a school that is not only just an online school, but instead, a "brick and motar" school that just so happens to have an online program.
Now into my 6th class of 12, I am very happy with the level of education I'm receiving at BU. The work load is tough, but fair. Even as distance education learner, the e-mails, programs, staff and faculty responsiveness, and class discuss feel like the campus experience. It's a great program.