I purchased this bag for a Levada walking holiday in Madeira where I am at the moment. It has been used every day and has proved it worth. As with all LA gear it is very well made and generally well thought out. The Airzone system works well even in 30c. It is without doubt the most comfortable sack I have ever used in fact you can forget you have it on. Some niggles though: the side pockets need to be 5cm deeper to securely hold water bottles and I would prefer a wider waist belt. The "mobile phone" pocket on the shoulder strap of the 25L is only suitable for a bunch of keys; useful though. The stated sizes are also a little on the ambitious side, I would be interested how it was measured.