This bag was perfect in size and construction at a great price but unfortunately the front velcro strap is too high to seat under the stem so had to go with a bag that has the strap closer to the top tube. 5 star bag if it works with your bike.
I have been using this on my gravel bike as top tube "gas tank" bag and it works really well. I like that it is narrow and holds its shape which keeps it out of the way of my knees. I like to ride technical class 4 and have not even thought twice about the bag over very rough terrain. The velcro straps are sturdy and hold it securely. The zipper is easy to work one handed, so all good on that front as well. The side pockets do not do anything for me, they are very narrow and I wouldn't trust having trash wrappers stay in them. Maybe 1 gel would stay ok, but anymore would be tight. I have thought about a second one as it can also be mounted to the seat tube.
This bag stays secure and holds just enough snacks. Perfect for clif bars and a phone. Side pockets are great for stuffing the wrappers back in. I like to carry more when out on an adventure, but for a few hours on the road bike this is my choice.