I have used Codio for teaching programming, specifically Python. Overall it is a very impressive package. No one had issues accessing it via Chrome, Edge, or IE. It did update grades in near real-time in Canvas. It was fairly comprehensive. Overall very good. The slight downsides that I see are that the administrative aspect of it seems to be a lot of work and not very intuitive, there are a very few mistakes(although I have seen that in all CBT software), and for a very few student exercises the instructions were not clear. Overall I would say it is very good, better than most I have seen, but a little over complicated.