Reduce is awesome! Dozens of specialized packages[1]. My favourite two packages are
1. The Source Code Optimization Package, SCOPE. It will take an expression or group of expression and produce a simpler set of expressions that minimize the use of arithmetic expressions.
2. The coeff2 package[3]. Tell coeff2 what the variables are and it will rewrite your expression as a simpler expression in terms of the variables alone and represent mush the others into constants.
I could not do what I do without it these two packages. Beats Maxima IMO.