I've had a HMG 3400 SW and my wife a Gossamer Gear Mariposa for 6 years. We got it for backpacking 5+ days in US wilderness, but they act as our one-bags across

I've had a HMG 3400 SW and my wife a Gossamer Gear Mariposa for 6 years. We got it for backpacking 5+ days in US wilderness, but they act as our one-bags across Latam. We didn't have a "one bag" mindset, we always just pack light. They collapse down enough that they easily fit underneath the seat on a budget airline and look like a college kid's backpack. And they expand enough they we've done multiple 4-7 day treks holding tents and sleeping bags (40L and 50+10L). And we roll up some smaller day bags inside for daily use.