Reliability of Sage vs commercial software
for future calculations I need a CAS. Up to now, I worked with a free mathematica student licence. But now I need a officially bought version (which I can't afford). I'm now trying to work with Sage but my head of department is no fan of open source projects and thinks, among other things, that it is probably buggy and not as powerful as said mathematica. Could you please tell me how "stable" and "correct" the sage calculations are and give me further information on this topic (I already searched the forum for some information) so that I can present him/them why we should use Sage and nothing like mathematica/mathlab/...
Please tell me if you need more information or clarification.
Thank you all in advance for your effort.