Prob I am a very small minority here, but I used Maple a lot in the past and I liked it a lot. More standard syntax than mathematica, and overall much much easier to debug. In particular, as far as I remember, maple allowed for more transparency in the mathematical methods used in some computation than mathematica, as I could just see what it was doing exactly when an unexpected result came or I wanted to understand some method. When you work a lot with integrals, limits and special functions there is always a shit ton of assumptions and cases all over the place, and if something is missed somewhere the computation can just get wrong. There were some few times I would actually get wrong results in mathematica. When the language is more like a black box, it is hard to know what happened.
>>freeho+(OP)
That is also my feeling, although it has been ages since I last worked with Maple. But some colleagues of mine at other uni do use it instead of Mathematica. Thanks for the detailed reply!