I basically like the pack but I do have some considerations. First, I would recommend Ortlieb use a double zipper. The single zipper pull, pulled closed to the side, would hit my leg with each pedal stroke. Second, for better and worse, the pack is wide. Initially I installed in one the top tube at the head tube and then changed it to the top tube at the seat tube. Neither position worked out because my thigh would hit the bag when it was in the front and I was out of the saddle, and it would hit my thighs with every pedal turn when it was attached to the seat tube. I mounted it on the down tube connected to the head tube. That has worked but I did remove the front water bottle cage. They would both fit in the space, but it was tight, making it hard to access either one.
Really well constructed and light weight, like all of Ortlieb's gravel bags. But, having problems finding a bike to use it on where my knees don't bump into it. Didn't really work out on my gravel bike, that I intended to use it on. The top tube is too short, and the bag is too wide, my knees are always bumping into it, and it's just too annoying. Ended up putting it on my MTB (Santa Cruz 5010, 2019), which has a longer top tube, so very little knee contact. It is small in size, my Pixel XL barely fits into it. Should have bought something taller and skinnier, that would have worked out much better. My pedaling style is knees in towards the top tube at the top of the stroke, so not a good fit for this bag.
On my bike, the Ortlieb Cockpit Pack strap that wraps the top tube, lines up with the Ortlieb Top Tube bag straps therefore cannot use the two bags at the same time. The bag is a little small (shallow). Not very roomy. Hard to maneuver phone in and out with anything else in the bag. It's more of a one item bag (for my use).