Fairly comfortable, multiple compartments fit both my 14.1" laptop and 10" tablet pc, with chargers and other gears like hdmi cables, flash drives, etc. I live in an area where summer temperature easily goes over 95, so can't say much about the mesh- I'd sweat with any backpack.. But the straps are sturdy enough to hold up the weight of my books, laptops, stationeries and water bottle, so that's great! I like the front little pocket to put things I could easily grab, like keys or earphones - things I'd need to reach while on the go with things in my hands already. I have not had a chance to try out the usb port for the portable battery (not included), but I do think is a cool feature and is one of the reasons why I bought this bag. The lock that comes with the backpack works fine, haven't had a reason to put it to use yet; I figured it'd be more useful in situations like travelling or having to leave your backpack in a public library while you go to the bathroom or something. But hey, free lock- use it for your gym locker if need be. All in all, a great, sturdy backpack with lots of different pockets in different sizes to make compartmentalizing your iteams fairly easy and convenient. Just what I needed!