Serviceable but limited.
I used the (30L) pack for a 10 day trip to Peru with variable weather conditions. Think lots of thin layers. No laptop or heavy electronics. I had hoped to use just one carry on. Also had access to laundry service mid-way, so really packed for 6 days.
What I noted immediately was if you packed the main compartment, the “other side” of the pack was so compressed that it was pretty useless except for very thin items. If you reversed the packing the main compartment was compromised. So a balance was needed as was a second carryon. Not a big deal since that served as my day pack.
Admittedly, the extra layers took up space; but I have wheeled bags of similar size (30 L) that can hold more and more efficiently. I will try the T-bag for a shorter, say 5 day trip w/o a lot of layers and see if it works for that.
Pluses. Durable; comfortable to carry with ability to adjust the fit. I love pockets to organize and this has a ton; just that some were not useful with a fully loaded pack.
The straps as typical for a BP could be flighty and make stowing it difficult. I figured out a way to quickly tie down the straps, hip belt etc. using the belt clips to make it fit in the overhead easier. (See photo).
The constitution, comfort and durability make this bag a 4; otherwise, for storage and usefulness only, I would rate it a 3.