Familiarity: I've used it once or twice and have initial impressions
I love this bag. It fits snugly on my bike due to the two little rubber nubs that stick out from the bottom of the bag which help with grip. The two straps are easy to attach and even work with my aero bars up front. I have one of the large iPhones and that fits nicely inside, even allowing room for a tube and other stuff to be put in there alongside it.
The bag features a port on the front that is kind of an "up and over" setup, with the wire coming from inside the bag, over the internal wall, and then out from under the hard flap in the front and the bars. This would facilitate carrying a battery in the bag for long excursions where one would want to power the Wahoo/Garmin for extra innings.
The zipper pull is a nice touch in that it is easy to grab even with gloves on and riding at speed, while the elastic wiring on the right side of the bag allows one to attach some extra stuff if need be in a pinch like arm warmers or a vest.
Leg clearance while pedaling is a non-issue. Color is very nice and compliments a variety of frame colors. All-in-all, happy with the purchase and it will continue to get used often.