I'll tag along on this thread with my 2C:
10-10
After trying many lubes for MTB over the past 15 years, there's one i'm liking more than any yet: PURPLE EXTREME.
On first-use, this stuff seems so thin one might ask: "how can a substance this thin and watery possible set-up right?" Well, it amazed me. As thin as it goes on, ...An hour later it leaves a tough coating...a super thin coating that resists moisture and dirt. The beauty of PE is that, due to it's thin-liquidy nature, it seems to rinse out all that was there before....everytime you use it...only to leave a lovely coating again.
In other words, there is NO buildup whatsoever. A little goes a long way, so if the price seems too steep, don't worry, you don't need alot of it.
My chains have never been happier, shiny-clean, dirt-free.
IMO it gets a 10 rating.