How does Octave or any other open source tool hold up against something with so many resources behind it?

Background: I'm an ECSE student who has used both throughout my course.

Octave is very much like LibreOffice - it's usually good enough to use instead of MATLAB, but it's not perfect. Most of the functions are there, though some which are commonly used but not strictly necessary (e.g. importdata) are not. Octave's syntax is also looser than MATLAB's (you can use ! instead of ~ for logical negation), which means that you still need to test a program in MATLAB if that's what the recipient is going to be running it in.

Its main advantages are its cost and size - Octave is free and a full installation is 42 MB, whereas MATLAB costs tens of thousands and takes up about 5 GB. MATLAB also has rather cumbersome DRM that can cause issues.

The main disadvantage is speed. Running a SVD on a largish matrix (e.g. 350x350) is one or two orders of magnitude slower under Octave compared to MATLAB. i.e. it takes 10 min instead of 10 seconds. That's a pretty niche use though - most of the computations people use MATLAB for aren't particularly intensive.