Best chain lube (IMHO) is 90w gear oil, dribbled on after a ride when the chain is hot. Thicker oil stays on longer. It is also way cheaper than spray lube.
My evidence: 36,000 mi so far on an O-ring chain, lubing every 350 mi or so.
I like that Dupont product because 1) I can be a bit lazy about cleaning chains, 2) Price at Lowes is decent, esp. when compared to boutique MC chain sprays, 3) While I try and stay to blacktop when I'm out rambling (street tires), I like the fact that the Chain Saver material is continuously shedding dirt as I'm driving - nice when I'm connecting dots on the map and end up on dirt roads.
That's high miles that you've racked up mvwicker, it seems to be working well for you. A basic lube, applied consistently, works wonders on chain/sprocket life - That's the premise behind the auto-oilers many guys like.
For folks that won't/can't take care of chains properly, they are much better off with a belt, IMO.
Rgds, D.