I used this bag for almost an entire year and it’s got plenty of room at 20L. It packs nicely into itself so you can easily stow it away which is a nice perk. My only gripes with it are that the side pockets are a bit flimsy, especially if the backpack isn’t full of stuff, so my water bottle would often fall out. Also, if the bag gets wet then you’ll notice the lining start peeling away and getting on your things.
All in all, I’d recommend it for the price!
Here’s a link to purchase the Hikpro on Amazon: http://amzn.to/2ClByEt