I really like Deuter products. This included. Plenty of room without being heavy, well made, well thought out. The reservoir is also nice. The mesh back is comfortable and lets in air. I use it mainly for mountain biking, and occasionally for day hikes. For hard mountain biking in Utah, where hydration is king, the bite valve on this...well, bites. The fluid flow rate seems significantly lower than a Camelback bite valve and results in getting less H2O when you are trying to get fluid while almost anaerobic! I swapped in the Camelback bite valve and now am very happy with the product. If you only use it for hiking, the Deuter bite valve works fine. But if you are dying in the desert, swap it out!