@louiscouture I've used both heavily at different times. Octave will accept pretty much all valid Matlab code, but the reverse is not true (Matlab doesn't support Octave's use of x++ to increment x, for example, and it's pickier about single vs. double quotes). So if you need to submit code for the grader to run, you should at least do the remote desktop thing afterward to verify your code is Matlab-legal. If you just need to submit your results, Octave's richer syntax is certainly nice to have.

Matlab's user interface beats the pants off Octave. In Matlab I could use the variable window almost like a spreadsheet to edit arrays in-place, delete failed commands from the history window, copy-paste large blocks of commands from the history window into my editor or command line, etc. Octave's mindset is different - the GUI is an afterthought and by default it just runs in terminal.

Matlab has better external tooling. There is a bunch of field-specific "toolboxes" but also a repository of user-submitted functions that you'll only have access to with a Mathworks account, and the licence forbids you from using those functions in anything other than Matlab as I recall. This may be less of a problem now with Github's increased prominence.