I’ve got the Vaude Alpine 30+5. In all fairness it gets used for commuting as well as riding, so I need the extra space. However, you have to undo a zipper to get the main compartment to expand to full size, so it’s a fairly respectable size most of the time.
There are more than enough pockets. When I go riding, I have all my repair kit, a waterproof, 2l hydration pack, lighter/heavier shirt, fixed lens bridge camera, work gloves, a decent amount of food, map and compass in the bag.
The weight sits fairly well on the hips and the waist straps don’t slip as you ride, chest strap works well and it has size adjust on the back.
The only downside is mine does tend to make a bit of a creaking noise as I ride sometimes. I haven’t really tried to sort it out, but it’s something to bear in mind if you get easily annoyed. I do recommend it though, it does a great job of carrying everything, and has compression straps on the sides, so you can keep it fairly compact if you’re not carrying too much.