The U175 is a dedicated Garment Bag and will of course provide better transport for a few suits at the detriment of packing capacity for other items like shirts, shoes, etc. It looks like a typical rolling carry-on, has the same rough dimensions, but it's essentially an old-school garment bag on the inside with its deep suit cavity, corner left/right 'shoulder' storage compartments, etc.

The U122CX is a best-in-class rolling carry-on (I adore mine) which is better suited for the business casual customer, it's ideal for dress shirts and dress pants in its compact folding suiter and then has amazing capacity and storage options for t-shirts, underwear, charging cables, etc. It's known for its compression technology where you can overstuff the bag and then ratchet down its size so you don't get in trouble with gate agents.

So it depends on what type of traveler you are. If you have a 5 day trip where you must bring a minimum of 2 suits with several shirts and ties, you would keep your U175 for the best chance at a wrinkle-free experience. If you have a 5 day trip where suits aren't necessary and/or just a sportcoat will do, you would definitely want to trade it in for the U122CX.

BJ