Hi,
I have a Dive Rite 21W HID Wreck light. I have used it for more than year now. Did some wrecks in the Keys (Duane, Eagle, etc) and night diving in Cozumel.
PROS
1. 21W HID - Wow! Daylight at night.
2. The beam is widely adjustable - narrow to wide
3. The 9-amp NiMH battery has a long life.
4. The bulb goes on when I turn it on, stays on until I turn it off.
5. It has never flooded on me.
CONS
1. The head seems flimsy and very fragile compared to other brands
2. The thumb screw that holds the reflector in place strips easily (screw is nylon)
3. The Goodman hand mount clip doesn't fit the 21W head - you gotta custom mount it yourself
4. The screw that holds the reflector in place has actually fallen out on me - luckily I suspended the head, reflector and Goodman mount together, so I didn't lose anything. But had I attached the bolt snap to the ring at the back of the head, I would have lost the reflector into the night.