So I posted a thread last year about 3 weeks in Europe where I was trying to decide on a bag - I ended up going with the Aeronaut. It worked great for my needs, but I found myself overstuffing it and needing to carry it, overstuffed, as a backpack for extended periods of time. While I imagine it was the most comfortable a bag with a 45 liter capacity strapped to your back could be, it made me realize I want to improve my packing light skills so that I can carry a smaller bag next time!

My setup last year was:

1) Rolling suitcase
2) Aeronaut
3) Western Flyer

I have an upcoming trip that's going to be a bit longer, and I'm thinking about replacing either just the Aeronaut or the Aeronaut AND the Western Flyer with another backpack-style bag.

My first reaction is the Brain Bag - from looking at it, it has a slightly larger capacity than the Tri-Star, and what really caught my eye is that the back of the bag appears to be HIGHLY padded. The biggest issues I had with the Aeronaut, really, were its comfort against my back, which makes me nervous to try the Tri-Star, since its backpack straps and back panel look exactly like the Aeronaut, so I don't think the comfort will be much different.

I've read a few threads here comparing the two bags, but it seems like there's no clear consensus, and the Brain Bag appears to have been redesigned since some of the threads were written. Does anyone have experience with both bags? I know a lot of people mention that if the Brain Bag is full it can be a bit chaotic to find things in the bag, but given all the packing cubes and organizers I have, I'm not concerned about that - my main concern really is how can I most comfortably carry about 30-35 liters of stuff on my back in fairly hot climates.

I'm also considering trying to get down to just the suitcase and whatever bag I select (Tri-Star, Brain Bag, or ...?) and not carry the Western Flyer so that I only have 2 bags. I have one of the packing cube backpacks so if I need additional capacity at some point in the trip, I could always add that to the mix. But first and foremost, I just want to figure out the most comfortable way to carry 30-35 liters of luggage on my back, and then I'll figure out the rest.

Thanks for any advice you might have!