Nice cod there Mark! I had a little reef shark swim into my port a couple of weeks ago. Unfortunately, I had my 60 macro in, so all I got was a shark smudge.
It looks like I had better check this lens out. I had heard people raving about it but I wasn't aware that it was a FE lens. I suspect I could sell my 12 - 24 and get by with one lens easily enough, and for not a lot of bling...
Thanks everyone. Feel free to carry on the discussion! 
Hey buddy
I started off shooting the 10.5 FE - as I could never get the 12-24 to do what I wanted it to do. The 10.5 FE had such a great DOF, and every shot just worked, This was back in the D70 days with an Ikelite. I just couldn't get a clue with the 12-24 back then.
Then Ike released the "bigga Dome"... all was right with the world.
Shortly after, I moved into the D200 and a couple of Light & Motion housings. That big 10" glass dome was sweet.
As the years went by, my 12-24 with an extension and a 2X on that huge glass L&M dome became my go to lens for all W/A - the 10.5 FE was just a drag to light. I don't dive in pristine waters - I dive in SoCal. Its dark on the best days, and green most of the time. That means getting real close. Easy peasy with the 10.5 FE, but when I was shooting people with it, it was so hard to light them without consistently getting the raccoon mask effect. The 12-24 was such a great lens for what I was doing. CFWA, portraits, Sea Lions, etc, etc, etc.
I pounded the 12-24. Year after year... getting better and better with it. I loved that lens. The 10.5 just sat in the bag trip after trip.
In November I moved to the D7000 and the Nauticam D7000 with the glass mini-zen dome. Sold the 10.5, and bought a Tokina 10-17. While I desperately miss the '24' of my 12-24, I am starting to love the Tokina.
I'm not a big fan of the Tokina above water - I still use my 12-24 for most dry interiors, as its not nearly as fishy as the 10-17.
I'm on the ragged edge of selling my beloved 12-24. I bit hard and bought that when I got my D70 ages ago. It cost about as much as the body, and more than I paid for the Ike D70 housing! I've had that lens for as long as I've been shooting DSLR (the Oly E10 and E20 don't count!) - I know I'll never use it underwater again, as long as I'm shooting the D7000 and the Mini Zen dome.
I was a total non-believer in the 10-24 Tokina. For years and years. But I've done a 180 on it. I blame Geitler and Canon for that! Scott and Ryan spun me around on the Tokina.

Now the 10-17 my only W/A lens.
-Ken