Size wise it's not huge. If you're thinking of one of those very large hard sided rolling bags, this is not it. They could stand to make one at that size point. It's hard for me to say if it will do a 3 week trip as different people travel differently. For someone who is a medium to light packer, probably.
For my wife and I, it was one of two checked pieces for a three week trip. The other was a RedOxx duffel into which we packed cubes of mainly clothing. The roller held some hanging clothes in a sleeve in the lid size, some fragile dress shoes for my wife and other items that needs some hard side protection that we didn't want to pack in a duffel. So it fit our needs well.