I use an Abus Granite Futura mini lock and love it. It replaced an orange Kryptonite Evolution series lock that weighed about three times as much. Surprisingly, I don't miss the extra room of the Evolution. I'm usually able to get my Abus lock through the front quick release wheel and frame of my bike when locking to a ring-and-post. Sometimes, I need to go a block out of my way to find a proper ring-and-post, but its usually not a big deal.

If there is any inconvenience to having a smaller lock it is more than made up by the weight savings, IMO.