This program is very well made. The symbolic factorization is a big plus because you can enter the polynomial "as in the textbook". The author also gives an alternative program where you enter the coefficients one by one, for people who prefer the traditional way. I also like how the answer comes out in the graph window in small text, very nice when you are factoring a giant polynomial with many factors.

One drawback: the program only finds rational factors. In other words, it won't simplify factors with square roots or imaginary numbers. For example, it will factor x^3+4x as x(x^2+4), not x(x+2i)(x-2i). This is not a major problem, though, because the majority of the time you can factor out the remaining factor by hand with other methods.