I use a cheap plastic Caldwell rest. It seems to work just fine for me. I also have Caldwell bags (for hunting) that are filled with rice. Both of them are good rests. The thing I have changed in my shooting regiment is the manner I address the rifle.

There was a show about snipers and they showed how they held their rifles on a rest. I started to copy what they were doing and it has improved my groups a great deal I believe.