The BD Camalots need no introduction. They've been plugged into rock across the globe, solidifying their synonymity with the phrase "Spring-Loaded Camming Device". The dual-axle, four-lobed head of the device allows for fantastic expansion, making it easy to pick the right size every time, even when you're feeling pumped out. The thumb loop really does improve the user-friendlyness of the device, and is a much appreciated feature.
I own camalots and have found no flaws with them. HOWEVER! I wouldn't discourage anyone from checking out DMMs Dragon units. When BD's patent on the single-stem, dual-axle, quad-lobe device ran out, DMM jumped on the bandwagon and produced an equally stellar item. The dragons are lighter than the camalots, they're super durable, and they come with a neat extendable sling. While I've used the extended sling with some success, I often find it frustrating to unclip the carabiner and reclip it through one strand, only to have it extend out as far as a quickdraw would have extended. This aside, the dragons are an extremely attractive substitute for the camalots, and I would strongly encourage checking both products out!