Wilson Combat rocks.
I like the vang comp. Most ghost rings need the front sight silver soldered on. a couple use epoxy, but after having one front sight fall off during recoil, silver soldering is the only way to go. Casey at TacOrd does Vang Comps
Casey X2
http://www.tacord.com/index.htm
X3 quick easy to deal with.
I just installed a Vang Comp set, they are very nice.