While getting accepted is obviously not a given, the program's admission rate is very high. The founder, Zvi Galil, is on record speaking to the philosophy of democratizing CS education that motivated the program.
Which is a flowery way of saying that getting into OMSCS is much more about affording it than any other similar program.
Getting out with the degree, however, requires some serious commitment.
-Disclosure: I am currently a student in the program.
If you take some of their online courses or a MicroMasters program and do well in them, they'll probably admit you to the online Masters program. Note: I work at edX.
I didn't mean to imply that. Sorry. If you can get accepted and if you can complete the work, then it's a good program for you. But, yes, it is very difficult (as it should be).