Get this...



... it's head and shoulders above the models you are looking at and ranks as one of the best.

Kryptonite New York Fahgettaboutit Mini Bicycle U-Lock

I think the ratio of bike $ relative to lock purchase formulas out there are pretty silly. I don't care if your bike is $280, or $10,280 - spend the 20 bucks extra and get the best lock. It's worth the emotional cost and inconvenience of having your bike stolen.