I used a Chest Strap with an FR630 last year and loved the running dynamics but hated wearing the Strap. I have been using a Fenix 3 HR since and, whilst great, missed the running dynamics so was waiting for the FR935 to come out as compatible with this Pod. It works great and has all the dynamics you need and no Chest Strap needed :) It's tiny but clips onto your shorts tightly so hopefully wont loose it, but it's probably going to end up going through the washing machine at some point so hope its waterproof? (there is a handy reminder to remove your pod on the watch after a run). It turns itself on and off so its extremely easy to use and just does its job very well.
Bought this for my wife who has the new Garmin 645 music to pair it to. She is new to runing and was looking to use the advanced metrics to improve the efficiency of her running and reduce the risk of injury. She hasn't got a bad thing to say about this pod, its tiny and she doesn't know its there when clicked on the back of her belt, and gives all teh stats she needs from her runs.
This thing is crazy small, and in just a couple of weeks has survived a fall during a run (note if you lose it: upload your data and look where it ends - don't just go out looking for it!) and a trip through the washing machine, so it's impressively tough.
On the negative side, the clip doesn't have the strongest grip on your shorts, and it's pretty easy to cause it to pop off if you're fiddling with the bottom of your tshirt. A secondary mechanism like an inward-facing pin on the clip would help it to grip a lot better.