It says that Maxima also has its own programming language (written in Lisp). Any opinions on it good or bad?
Maybe if you come from a CS background. From a math background, it's syntax is actually more natural than most contemporary programming languages. For example, : is used for assignment, because = has the normal mathematical meaning. Blocks use parentheses because that's how you group stuff in math.
Maxima is very much a domain specific language, where the domain is mathematics.