I usually use a U lock ( http://www.hucknroll.com/planet-bike-super-guard-u-lock-standard ) for my bike. But when I'm rollin with a crew out and about I need a bigger lock. I went with this. It's burly, a lot heavier and thicker than I expected. Not something I can roll around my cross bar, now I always throw it in my pack. tubular lock is a pro/con at the same time, if someone knows what they are doing then they'll get it, but that is the case with any lock. Hopefully this deters someone or delays them long enough for us to catch them.
I use this for my mountain bike too, when I need to lock it in the back of my truck. ( I still haven't upgraded to a lockable rack ) I'm using the Yakima Bettyjo rack.