I have one also on my F3 Limited. It doesn't have a lot of storage but is nice for a wallet, gum, sunglasses, insurance card, etc. I really like the ability to strap some gear to it and have used the cargo net feature to hold down some bags from the store. I don't ride two up so the rear seat is not a feature I need.
Yes...it is very easy to remove...maybe a few seconds and put the other seat within a few seconds and than transition to easy riding in less than a minute total.
I thought the urban rack goes in top of the seat, no removal of seat is required?
Nope, the Urban Rack takes the place of the seat. The seat has to come off. Like shoes8 said, it only takes a minute to remove and replace with the seat. You just have to push the ignition key and turn it to the 'wrench' icon. This will release the seat. Pull the seat off and put the Urban Rack in it's place. You do the same procedure to put the seat back on. My wife loves her Urban Rack.