Argument in favor of Maxima vs mathematica / maple

When I told a colleague of mine, in general a supporter of free
software, who tries to develop the use of CAS in the university that
he should favor Maxima as it is a free software, instead of maple or
mathematica (that he uses), he answered that the language underlying
maxima was "the old LISP" while maple and mathematica were developped
using more modern technologies, hence, more powerful or at least
valuable for a student to learn. he also claimed that he was more
confident in a company supporting a software than a community, but
this is a completely other point.

I could not argue as I do not know Lisp (I have just started with a
tutorial) but I would like to collect argument from the list members
and put them in the wiki eg at
http://maxima.sourceforge.net/wiki/index.php/Supporting%20arguments

I would also like to have an idea about high schools or universities
using Maxima in effective underraduate or graduate education, and
again put this in the wiki eg at
http://maxima.sourceforge.net/wiki/index.php/Example%20of%20use

Thanks,

Nicolas

-- 
Nicolas Pettiaux - email: nicolas.pettiaux at ael.be