I have a true love / hate relationship with MathCAD.
I love the programs for some of the calculations I do. Just very easy to use, and intuitive.... Though it has gotten less so over the years.
I hate all the games the company plays:
a) They're constantly changing their file format, so that the newer versions can't open older files.
b) No backwards compatibility at all. A way to force customers to upgrade if they need to read someone else's file.
c) A single license on one computer isn't terribly expensive. But, they really, really charge you if you want to turn that single copy into a single concurrent license over a network.
Back when I was at RISA, I suggested creating a RISACalc package that would do the basics of what MathCAD did. Just give a simple program for writing equations, formatting and citing equations in a WYSIWYG interface. I thought it would be great to tie into RISA input/output. But, management had no interest in the concept.