Ive had this bag for over a year now and have a few things to report. The mesh that sits against your back covering the exolite holds heat and sweat in like crazy. On short 4-6 hour day hikes in the summer your back will be soaked. The mesh material is also not durable at all, mine is coming apart along the waist line. The chest and waist strap are mediocre at best. The bag is definitely not waterproof and only water resistant if your not going far. The pros of this bag are that it is great for carrying your schoolbooks and laptop. I use it constantly for traveling on 3-4 nighters to visit friends or family or whatever. Lots of room and very versatile. Perfect for some but definitely not all.