The Split Strap is as comfortable as advertised, and despite some initial reservations about it possibly getting a little grotty-looking over time like other Neoprene products I've used, it seems to be wearing pretty well.
I don't particularly like the strap webbing, however. It's too slick and is starting to show wear after only a few months of not-terribly-intense use. It's too floppy, and there are no 360-degree-rotating connectors in the whole system to prevent the strap from getting twisted.
There's also so much plastic on it that it makes a small racket when you're cramming it back into a bag, which might get embarrassing if you shoot in quiet environments. Ironically, though, it has only one cam buckle to keep the mount from sliding too far back or forward; I prefer the BlackRapid Sport Slim's double cam-buckle system. You can always move them out of the way or remove them if you need more sliding latitude.
One of the advantages of CustomSLR's modular system -- and the ingenious design of the C-Loop -- is that you can use any strap you want with it, as long as you can get the plastic quick-release connector on it.
If you need something a lot more comfortable than the bundled strap that came with your camera and like the convenience of a sling strap, this is a great choice.