In reply to Mick Ryan - UKClimbing.com: I used the both the Eddy and the Faders Sum last weekend - and it was very interesting to compare side by side these two as they both want to be new grigris. The thing that I found most about the Eddy was that the second lock postion meant that you couldn't get much control over the speed you lowered - it was either lower or don't, the only way to do it slower was to hold the dead rope down to increase the angle of entry just as you would do with any bog standard friction belay device like an ATC or stitch plate.
The Sum in contrast has a lower of lever that has to be pressed in to lower. It has a very strong spring meaning you need strong hands - not a problem for most adult climbers but I imagine some youngster might find it difficult.
The sum is mechanically simple, smaller and lighter - I really couldn't decide which I preferred. I need to belay leaders with a bit more to see which feels better paying out. I've only started using a grigri regularly recently, and paying out seems a nightmare, perhaps I need more practice with that, but both the Sum and the Eddy seemed a bit better at first and quick use.
