I purchased this for the garment bag. But I don't know that I actually need it given the size of the bag. It is much larger than expected. However, I purposely purchased this bag because it reached the maximum dimension for a carryon on most carriers. The garment bag does zip out which is a good option. I used it once. It kept my clothes fine. I was using it more to ensure the dress for a wedding has some protection. I like it as a regular carryon without the garment bag.
I have used it for two road trips and a flight on Southwest from DCA-STL-MCI with no problems. I was able to pack quite a bit without expanding it. I was concerned given how much it holds. It looked real fat and would not have fit in the sizer at the gate and ticket counter (but whose carryon actually does?) And when I put it in the overhead it seemed to stick out. But it fit in the overhead easily and there was no problem with the door closing. There was still some clearance, so I think you could use the expansion and be fine.
It seems sturdy. This is my first hybrid bag. It's not as hard a case as I thought which is good in terms of having some give. I like that you can really pack two haves and keep clothes separated. There are two front pockets and one will easily hold a laptop. Empty, I was concerned about its weight, but it rolled easy through the airport and was light enough to lift. It has a bar on the bottom so that helps with lifting. And it never tipped over when standing upright.
The material seems to be holding up, but I expect my luggage to take a beating. I am not expecting this to last for 20 years with regular use. Unless you are spending over $@#! for a carryon, I think quality wise there really is not a difference between this price point and a $!@# carry on, other than the name.