In reply to annakyn:
For climbing up (as opposed to downclimbing) its really no different to using an ascender. The toothed wheel doesn't turn that way, the teeth just 'ride' over the rope like the teeth on an ascender cam.
What you pay the extra money for (as an industrial user) is the way it has to be 'dragged' down the backup rope as you abseil on the main one. The toothed wheel rotates as it goes down, and there's just enough friction that the device as a whole stays above you, keeping the potential fall factor down.
I've never used an ASAP when climbing for fun (I have used a Rocker a few times). I've used both in a similar situation to protect a climb up a truss tower at work - going up there's nothing in it, downclimbing the ASAP is marginally better, its less prone to jamming and it stays above you on the rope. (The rocker is actually below you until you fall past it, though it does occasionally jam and need to be moved down the rope by hand.) Those teeth are scary, if you made a habit of downclimbing I suspect they'd inflict a lot of wear and tear on a dynamic rope.
For my money, a Rocker is better. Its also cheaper than an Asap (they're not that similarly priced, though both are more expensive than a Shunt).
hth
Sean
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