Just out of interest, why is the can light so good, is it the sort of diving that you do or something else?
A really great question. Makes me realize that is tough to answer in an objective way. But, I'll try. I think the important elements of the answer include, I like having a light, and I like the convenience, reliability, and function of the can. For background, I have a 10W HID Dive Rite. The 18s are probably brighter, the lights with adjustable heads are probably even better. But, I love the one I have. The type of diving I do may have a small influence. I like wrecks, so having a light to peer into nooks and crannies to see what marine life may be hanging out there is useful. Even for daylight, good visibility, diving on modest depth coral reefs, it is nice having a light for that purpose. I bought the can light for tec, so part of the diving I do is now a bit deeper and consequently a little darker. Notably, I dont do much night diving. I like the convenience of a can light, where I attach the weightier part the battery - to my waist (or BP), and have only the minimal weight light head on / in my hand. With the can, and the light head strapped to the back of my hand, a hand that used to be occupied holding a portable light, and getting fatigued from the weight, is now relatively free (I happen to use a light head with an elastic strap rather than a Goodman handle, but I expect I would feel the same either way.). I like the (perceived or real) reliability of a can light. I dont worry about whether the light is getting dim because the batteries need to be changed. Of course, I have to make sure I charge it before a dive, and that I take my charger with me on multiday trips. But, it has a four hour burn time which exceeds my (single) dive time. It provides brighter, or at least 'better', light than any portable light I have used (including a UK Light Canon). Finally, I appreciate the stowability. When I am ascending, or back in a bright zone, I turn the light off, clip the head to my harness D-ring, and stow the cable, and I dont feel that I have a boat anchor dangling from my chest the way I did with portable lights.