I'll second that. I own a Salvo 12w that I use for wreck diving in the Labrador Current and also cave diving and it does fine. It's not pencil tipped like some HID's, but nobody has ever had a problem with my signals(it's not as unfocused as the Dive Rite LED's either). Also, something I like about it, is how much spillage it also gives. It will light up the surrounding area much better(at least in cave diving) than the few 10w HID's I've tried, while still giving you a usable hot spot.
Lithium batteries are the way to go. They hold more energy per unit of volume in our applications. None of the batteries used by salvo come anywhere close to the airline restrictions/UPS restrictions so don't believe any of that BS some idiots talk about. Lithium batteries also have longer lifespans than NiMH. The rest of the world switched over to lithium batteries YEARS ago, so the only reason NiMH is still so prevalent is because the diving community is worse at accepting change than the military(I can comment on both). The Salvo canister on the 12w is awesome, it's incredibly smooth/no latches or anything to snag, and it's really about the size of an energy drink can. No ****.
It's not such an awesome light that I'd go out and buy it if I already had a Salvo or Sartek 10w HID, but it's definitely one of the best choices if you're looking to buy your first can light. Another to look at is the Sartek 6600, but this Salvo IS sitting in front of your fingertips as you read.....so........
One more thing: When Salvo released this light they discontinued the 10w HID because they couldn't find a reason to keep making it as they thought the 12w LED so much better. Still, dinosaurs wanted the 10w HID brand new, and so they put it back into production. The HID also costs $100 more than the LED, even though the LED is better on every count.