I actually ordered the incorrect luggage and was thinking about returning this. I had been looking at and researching a similar Delsey carry-on, but with fabric sides. This one has a hard plastic shell, which is not very thick - it's flexible. The benefit of this design is that it is extremely lightweight. The rollers work well, and everything is fine.
The disadvantage to this design is that it doesn't have all the outside little pockets to stash stuff, like toiletries, meds, etc. It does have some pockets on the inside, and there are different dividers inside to keep your stuff organized.
I don't think I'll return it, but I don't think I'll buy it again. I like having those outside pockets!