The Osprey Farpoint is a great pack for general travel or backpacking abroad. I bought mine for a two week Europe trip and wasn't disappointed. I opted for the 70L pack over the 50 simply because I am not much of a light packer. It has nice internal cinch straps as well as external ones that allow you to fit A LOT.
Will it fit in the overhead compartment?
I was worried about it fitting in the overhead compartment while flying, but haven't had any problems. I think it is technically over the dimensions allowed for most overhead compartments but I have flown domestically without checking it on Southwest, Virgin America, and Jet Blue. No guarantees, but generally the worst case scenario is you have to gate check it. I still use this pack as my main travel bag instead of a suitcase.
I am 5'6 and 115 and am using the small size.
Daypack as a laptop bag
The external daypack that zips off works nicely as a laptop bag. It doesn't have a lot of padding for protection, but I prefer the lightness compared to my heavily padded bag. I use it as my primary laptop bag for my 13" Macbook Pro. There is plenty of room for it in the pocket that is normally used for a water bladder. It works nicely since the pouch doesn't span all the way to the bottom of the bag, thus offering some protection when sitting the bag on the ground.
It also worked fine with my last laptop which was a 15"6 MSI A6200. It was a tight fit though, and the bag would stretch to the corners of the laptop.
Does it work for camping / backpacking?
I have used the main bag when going camping. I wouldn't really recommend it as a primary camping/backpacking bag though. When the daypack is zipped to it, it feels off balance. Without the daypack, you don't have any external pockets to pack any small items (headlamp, cliff bars, chapstick, etc). It would work fine for car camping or short trips where you don't hike for long.
Overall, I love this bag. It's been great for a lot of uses and is way more practical than a suitcase. The daypack is great for day hikes, as a laptop bag, or your favorite touristy activities.