I did a split 10 gallon batch with 3724 and 3711.
In my experience:
3724 takes awhile (3-4 weeks, tends to get stuck around 1.035, prefers warmer fermentation temps >75 F, and takes a long time to drop clear)--I agree w/ Denny--it is more estery.
3711 is a rocket (done in 1.5 weeks, does not stall, does great in the low to mid 70's, and drops clear quickly)--it is also estery, but has a touch more phenols (esp pepper).
I personally don't think the difference is huge as both will give a person an unmistakable impression that they're drinking a saison.