I looked at a lot of bags for an upcomming trip to Europe. I have used many types of bags over the years including travel backpacks (do not go there if you can avoid it).
After all my research I bought a rolling duffle from
Travelsmith. It even came with 4 packing cubes. It is sturdy and has little feet so you can stand it up on end with out tipping over. I love it because the main compartment unzips down the sides so you have total access to the inside of the bag. Plus it was only about $120.
I find that Travelsmith products are decently made and last.