We recently had an issue where one of our U-locks stopped working.  We asked for feedback on our Facebook page.

Here's what other cyclists recommended:

Abus Granit Plus 640

Jason and Andrew recommended the Abus U-locks. The Granit Plus 640 was specifically recommended.

Abus Bordo Granit Folding Lock

Lauryn from Asante Cycles recommended her Abus folding lock, and Dominik seconded her opinion.

TiGr Mini

The TiGr Mini is super-lightweight and made of titanium and comes recommended by Scott.

Kryptonite New York

The Kryptonite is a beefy, high-security solution that was recommended by Warren.

Litelok gold

Litelok Gold

Another lock that we're considering is the Litelok Gold.  Lightweight and easy to use.