This bag is a great way to pack what you need and assure its dry when you get where you are going.Easy to put on and take off your bike and provides ample storage. I have used this bag many times and would purchase it again
I use Salsa's Anything Cradle on most of my bikes, so in some ways this pack is redundant. I already have an excellent way to affix a pack to my handlebars. But the nature & quality of this pack still makes it an excellent addition and value to my bikepacking kit.
First, when used by itself, it attaches securely to flat handle bars. I bought the long version; my GF has the short version she uses with drop bars. Foam pads space the bag from the handlebars and also the steerer tube. Velcro straps affix to the handlebars with a cinched orange strap providing an extra layer of security over the velcro. Well thought out.
Second, this bag is entirely waterproof. It has two of Ortlieb's signature reflective patches. Has an air-purge value to help make it compact with minimal effort. It is just a well-made bag for touring in all conditions.
Third, the bag is bigger than those made by Revelate and Salsa (which I also own). SIgnificantly larger diameter and about as long. So it is easier to pack bulky stuff like tents -- with poles -- and sleeping bags without fussing endlessly to make things fit.
Since I do have an Anything Cradle (a superior attachment system), I use this Ortlieb bag as just a waterproof pack. And it works great for that purpose.
Your main choice is simply sizing: if you're using drop bars, you're limited to the smaller version. Otherwise, get the big one.
I used this handlebar bag across my handlebars of my fat tire bike for my first bike packing trip in April 2021. I carried my 3person 3season tent (mutha hubba) and it fit well and I was able to stuff in a couple smaller items on the ends of the pack. I liked that the back opens on the ends, so I could leave it attached to the bike and pull out what I need, and put back in, without having to re-roll/reattach. It fit very securely and didn't bounce around at all as I was riding. This pack is waterproof, and it feels very solid..I feel confident that it will last a long time! I absolutely love it!