I have had the Osprey Porter Travel Duffle 46 for over one year now and have taken it on over 20 trips lasting from 2 to 14 days. And on those trips, with the occasional addition of a small laptop case, this has been my only piece of luggage. You can fit a surprising amount of stuff in this bag, and then using the straps, squeeze it down to such a small size.
Since I have purchased this bag I have been on well over 40 flights and not once have had to gate check my bag or store it under the plane- not even for the most packed up, tiny plane. Gate crew just see a backpack and don’t flinch. That said, I very infrequently fill it to the brim. But even when I do the flexible size and sides allows me to squeeze or position this Carry-On Duffle Bag in places that a hard sided wheeled carry on cannot possibly fit (including the small overheads on small planes).
What I also like about this back is that it allows me to carry it hands free. This is why I traveled with a backpacking pack for many years. But those top loaders were a pain to get into. Getting at something on the bottom required the removal of everything else. The double zippers on this bag allow you to get right into the bag just like a standard roller, but with the added benefit of carrying on your shoulder or back.
One last thing. I live in an apartment in San Francisco. Space is a commodity. I have many suitcases. Using the straps this bag will fold down to a small size and fit in just about any carry on we have. It takes up almost no space while holding as much as suitcases that take up twice as much space or more. I could fit the Osprey Duffel Porter just about anywhere. So when I’m not traveling, my travel bag is not taking up space.
Much like with backpacking, learning to “use” the Porter 46 requires a little thought that will make your life much easier in the long run. I use a double sided packing cube for the bulk of what I’ll bring, a small stuff sack for dirty clothing, and a zip out hang up clothes foldy-thingy from a previously owned wheeled carry on. With this combo I have packed for business trips, tropical vacations, cold east coast winters, and even ski boots and the works to bring to the mountains. The more organized you are walking into your trip the better you will use your space and the less time you will spend shoveling through clothing while traveling.