Last time I use Octave for my NLP class assignment, I have to create some sort of Matlab stub to make it work since the scripts from the materials provides has many 'version checks' inside, besides that it works perfectly. And I encountered some compatibility issue the other way (Octave back to Matlab) because the professor uses Matlab to run the code we submitted to grade them.

Good choice if you don't want the whole Matlab monstrosity on your computer, but still have to deal with some itty bits.