the matrix is better than the x-ecutor only because you can re-flash it.
If you don't have a modchip then get the new x-ecutor 2 that is comming out soon. Unlike the first one, it is re-flashable. Also this chip will work on any xbox, even the new ones.
Check out the x-ecutor site for details:
http://www.x-ecuter.com/
Also, this chip is a no-solder (actually, you have a choice of 3 different methods of using to install the chip).