My housemate and I are middle-aged folks who don't have a car--so we use this rolling knapsack to haul our groceries home, usually on the public bus, or occasionally walking. (Probably averages about 15-22 pounds each time on the bus?) The fabric handle on top is nice when lifting it onto a bus. I also like that it is compact, and not heavy at all, but yet it rolls nicely. We've had it a little over a year, and it still works fine. The retractable metal handle sometimes has to be played with just a bit to get it to retract all the way.  But this isn't a serious problem, and we can get it to retract when we need to.

Update, April 2016: We still have this thing. Bar on one side of the handle is now permanently in the retracted position--but I can still use the handle to pull it down the street. Top handle is still in great shape, despite being frequently used to lift a full pack onto the city bus. These days, I only use this pack about half the time, and use another rolling pack the rest of the time. Still, I would say it has held up reasonably well, and I expect to buy another one.