Did you guys see tho thread on the Saiga forum regarding Scott's new tri-rail?
Apparently Scott sent tromix one for evaluation. One of Tromix's engineers posted a comment about how nice it was and a very nice extrusion. Scott corrected him and told him it was machined from aluminum billet, not an extrusion. The Tromix dude comes back and says Wow, the machining was so nice that he thought it was an extrusion. He was really impressed then.
The difference in strength between an extrusion and machined billet is night and day. Those cheapo $50-$70 ones you see advertised are extrusions. The $200+ ones you see advertised are billet.