There's a mystique around Mathematica's math engine. Is this groundless, or will you eventually run into problems getting correct, identical answers -- especially for answers that Mathematic derives symbolically? The capabilities and results of the computer algebra systems that I've used varied widely.

Hard to tell honestly. So far there was always some surprisingly straight forward solution If had any problems with the math engine. There is actually a lot of public research how equations can be solved/simplified with computer algorithms. So I'm optimistic. I also stumbled upon a few cases where Mathematica itself didn't quite do things correctly itself (rounding errors, missing simplifications, etc.). So maybe it's actually a little overhyped …