I have the Redoxx Skytrain for 5 months and have taken it to Europe and cross-country flight. I picked the Skytrain over the AirBoss because I liked its versatility (backpack option), euro-handle on end overall size closer to European carry-on sizes.

The Skytrain carries a ton and packs my suit just fine. Very happy with it. I also have a Redoxx rucksack coming because I wanted a "true" backpack for shorter trips that I could carry-on with a spot for my laptop that had plenty of space for clothes. On US flights, I think I can carry-on both the Skytrain and the rucksack since the rucksack (unless it's stuffed) would be my "personal item" to put under the seat in front of me.