It took some time to get used to their online system, but overall it was not bad. I liked that I could take a semester long class in only an 8 week session. My only negative comment would be that the professor can sometimes take a few days to reply to your emails. So if you have an accelerated program and have 2 assignments due per week, you need to be asking questions ahead of time, and not the day the assignment is due, or you probably won't get a response in time.
I'm laughing at the reviews saying the math and science classes are too difficult. My lab was a piece of cake compared to the equivalent lab I took in person at a university. If anything, it's unfair that you can take online classes when you're applying for a highly competitive major.
Bottom line, I would always recommend on campus classes over online classes. But if you just need to knock out a quick credit to meet a deadline, Rio is a good choice.