This is a sick bag. The expandable compartment makes my life so much easier. When its not expanded, I can use it as a carry-on and still fit a good week or 2's worth of clothing inside, shoes and all. I've never had a problem with not being able to fit all my clothes, shoes, and a hairdryer in there when the bag's expanded, even for month long trips, and I'm a heavy packer. It's super durable, which is nice because I usually have to walk 5 or 6 blocks with it to get to the bus stop. I've had this type of bag for three years and traveled to several countries, plus back and forth to college, and I still see hardly any wear.
I know it's not specific to the bag, but I have mine in bright red&yellow plaid print and it makes finding it on the conveyor belt really convenient.
Also, I recently got the Dakine Valet Bag and they work really well together. It slips easily over the handles and sits right on top. (Not to sound like a dakine junkie)