So I have a 6 month old surly cross check that I commute on. I am able to store it in my office, so I rarely lock it up at all, only if I decide to bike to lunch or to a coffeeshop or to a friend's house.

However, I like to keep a lock on me just in case a situation comes up.

When I bought the bike I bought a Kryptonite Fahgettaboutit Ulock. I've tried to keep this lock in my backpack, and even got a rack to store it on, but this thing is so damn HEAVY. I never get stressed out about my bike getting stolen, but it's really not a practical lock to carry around with me in my backpack. If I ever go on a 3-hour ride around town, this lock just digs into my back like a mofo, and really makes the ride uncomfortable.

I am thinking about getting an Onguard Mini as my carry-around at all times lock. Will this be adequate for the ~1 hour at random times I have to leave my bike out in broad daylight?

Should I try to sell the Faghettaboutit or just keep it in case I ever need something super heavy duty (i.e. overnight or if start working at a place where I can't keep my bike inside).