I have a Mini and although it's light weight and convenient to carry, it's only locked on one end. From what I read, the higher end Kryptonites are locked from both ends, making it much more difficult to free the bike even if you cut the U. The Mini, if you cut the U, one side of the U can be pulled right out.
evolution mini
evolution mini
kryptolok series 2
evolution series 4
new york fahgettaboudit


"This is the Fahgettaboudit with 1 cut through. Notice that there is only ¾ of space between the cut bars due to the burly dual locking mechanism. Thieves have to cut through twice to get this lock off the bike frame."
http://www.outdoorgearlab.com/Bike-Locks-Reviews


These days, I've been using the Kryptolok Series 2 Integrated Chain. It's much more convenient and plenty tough.