No one mentioned my favorite Amazon review:
For such a sturdy, heavy-duty, ridiculously strong u-lock, the key used to operate this thing is ridiculously flimsy. The key snapped off IN THE LOCK the first time I tried to unlock my bike from a rack. >=(
Five minutes with a hacksaw only managed to scratch the steel. Seeing that I had to call in the heavy artillery, I got an angle grinder with a diamond blade. After about 20 minutes of 120 dBA flying sparks, I successfully extricated the bike.
I give the lock 5 stars, but the key rates a big, fat 0.
I looked into getting a mini lock, but after paying attention to where I regularly lock my bike I realized that I wouldn't be able to use a mini lock in most of the places where I lock my bike. It's too small.