Just joined the forum and saw this post, so hope my answer isn't too late. A few years ago I needed a smaller backpack (Delta carry-on) and was between the Osprey and the Mother Lode. I love eBags and bought the Mother Lode Jr but returned it for an Eagle Creek bag. I highly recommend looking at the Eagle Creek Cargo Hauler Ultra-Light Duffel Bag Backpack (the new version, not the old one), it's 22 x 9 x 12.5 in/40L and just 1.5 lbs.
Mother Lode Jr
The compartments are honestly what made me return this bag. I use packing cubes/ziplock bags (lighter than cubes) and found the compartments restrictive when trying to fit in all my stuff. I prefer one large space for more flexibility when packing and this just had too many small spaces. The water bottle holder is very nice but it wasn't something I needed. The bag feels very solid so I'm sure you'd be happy with the quality. As I said, I love eBags, my Piazza bag is a must when traveling but the Mother Lode Jr just had too much happening with it for me.
One warning, it's very easy to over expand it. I once watched a fellow passenger spend several minutes forcing the bag into the overhead. If you get it, just make sure you measure it before you go and again if you buy anything. It's also pretty structured which makes it harder to smash into overhead bins/under seats/etc.
Osprey
I nearly bought the Osprey but again I didn't want all the compartments or the extra straps around my waist.
Eagle Creek
Three main selling features for me: super light weight, large main compartment, and the main opening being against my back for safety. Since I bought mine they've dramatically improved the bag to the point I might buy the new one. The straps are now attached and store in the flap, whereas mine were removable (one "removed" itself from the bag while I was carrying it, thankfully I was using both at the time). They also added a compartment and a few other minor tweaks. I nearly always use public transportation getting to and from the airport/other hotels and it's very comfortable for 1 to 2 hours (5'4" female). The fabric cleans really well and it smashes down easily if needed. I was on an Embraer 175 once and got the seat with the half size overhead bin, after a few adjustments of my stuff the bag fit (I was not going to pay to check it since my bag wasn't the problem). The side pockets worked well for me for my liquids bag, dirty laundry/shoes, and anything else I needed quick access to. The straps are well padded and adjust easily. Overall, I really like this bag and use it often. The one downside if that if you have anything breakable like a tablet you'll likely want to get a padded sleeve for it since the bag itself won't provide any protection.
If you can, while I love my Eagle Creek bag, you might want to get one of the others if they have free returns and try packing it. Seeing how my stuff fit in helped me make my decision.