I locked my bike up with nothing but a bulldog mini for about 3 months at one of the worst places in NY to lock, right outside the NYU's Tisch School of the Arts building on Broadway. That lock up is straight infested with thieves, pretty much everything gets attacked at some point, they take the easy stuff at the beginning of the semester and then start chopping locks. Those $25 American Locks (the ones stores use) that people where using when the krypto/pic thing went down where a favorite target, they'd snip right through them and take both the bike and the chain, a double value. No one ever messed with my bulldog though, although eventually they unbolted my garbage richie front wheel and I reluctantly started carrying the chain again. Now that my bike is starting to get a bit nice I double lock with the mini as well...