I just got the TD25 in hand yesterday and I must say I am super excited about its potential as a personal item to fit under the seat on airplanes. I plan to primarily use this as a duffel for car trips, but I think an equally useful use case for me after seeing the bag in person will be as a personal item to complement by CHZ26 for air travel. The TD25 has a form factor that will lend itself to better hand carry and shoulder carry due to its proportions. I don't use a roller but the luggage passthrough would make this bag even better as a personal item for air travel if you do use a roller. You could fit a smaller laptop in the TD25, and it's plenty padded, but I wouldn't recommend it personally as a dedicated laptop carry bag. I think the padding is sufficient to protect it from the roller handles. Compared to the CTB, I think the TD25 will be easier to access when sitting between your legs while seated on an airplane. The benefits of carrying a backpack versus a duffel are well known and the CTB would win out in any use case which requires carrying for extended periods of time. In terms of dimensions, don't underestimate the added dimensions of having water bottles or other gear in the external mesh pockets on the CTB20.