Guess we'll always be striving for perfection, huh? So far all I've used is SPG for lubing everything. It's working okay. Just for curiosity I might try some others sometime. My only experience with hard lubes has been with some custom cast bullets I ordered once. They had some hard blue lube and white powder on them and I've never had anything that leaded like they did. It was horrible!
Steve Garbe has an interesting write up on lubes on the SPG web site that some may want to read about. I'm not sure I'll continue using his lube though. I tried to contact him to ask a question and he never would respond. I figure if he doesn't care to respond and give a customer a moment of his time I can probably get my questions answered by someone else who wants my business.