Just used ours for the very first time today (indoors).
Here's our takeaways:
1) Yes, it works, and works well. Catch feels progressive and doesn't seem to impede hauling in rope for a long clip
2) Surprisingly easy to get clipped in backwards (they have a big picture of a climber going upwards on the side and I still managed to screw it up twice...). I think it is because we're not used to clipping a draw prior to the first bolt.
3) A little too grabby on our used (but not super fuzzy) 10.1 rope. It wasn't a problem, but often after making a clip, the slack wouldn't make it all the way to the belayer. That being said, the benefit far outweighs the downside.
4) Our gym uses tape on the quick link to mark routes, this interferes with the orientation of the device when following the recommendation to clip in the quick-link and not the bolt. We pulled the tape and it oriented properly.
Despite the learning today, I highly recommend, it felt great not having to worry about pulling my belayer into the first bolt when taking a lead fall (195 vs 120 lb). It definitely felt better than when we used the weight bags.