Just a little update here for anyone interested in U-Box. I was able to move with U-Box and had a pretty good experience.
I had them deliver and pick up the U-Box from my Canadian residence at my own schedule, for the most part. I was in a smaller city so the requested date of arrival fell within a couple of days of the original request. Not bad at all. I'm sure if you are in a larger city, they can accommodate on the exact day you like
I was told it would be arriving in Florida from Ontario by October 14 and it was picked up in Canada on September 23. It arrived October 3rd! Pleasant surprise!!
It cost about $2500 CDN all in and was worth it. The U-box fits a LOT of stuff. If you're moving a 1 bdrm apartment or less I'd say you can get away with one. But again, that's relative to your square footage.
They will send you the customs form for you to fill out as well as an inventory list. I didn't have to do fully itemized, but I did a list like: Box 1 - Christmas Decorations, Box 2 - Office Items. If you have questions about the customs form or how to do your inventory, they have a specific email address they will provide to you with questions and they got back to me within 12 hours so it was pretty convenient.