Matrix isn't that bad. I bought a big container of it from Kensfish for not to bad of a price. The only thing I don't like about Matrix is they are large, they are like rocks. Works fine for cannister filters but stuffing my aquaclear with it isn't as easy.
They also make denitrate which is much smaller and functions mostly the same, it supposedly helps reduce nitrates but only if it's used in a low flow application (under 50gph iirc). Much easier to jam into a HOB filter.
I love my Matrix, I don't have any way to prove that it works better than any other bio media but it works well enough. Plus it doesn't seem to stain like some other bio media does which makes it easier to tell when it's actually needing a rinse.