I like miltec, if you apply it right it lasts forever and it doesn't collect dust and carbon, makes cleaning a little easier.
Edit: forever being a thousand rounds or so. Sorry for the exaggeration
Sgt. of Marines, 5th Award Expert Rifle, 237/250
1st Award Expert Pistol, 382/400
D Co, 4th CEB, Engineers UP!! OEF 21JUN-20SEP2011