I do not run one, nor have I ever seen them in person. I am a "reef light geek", though, so I'll give you my 2 cents.
Looking at the available info, I think I'd probably opt for the "regular" over the "blue". I say that because of the presence of cyan and warm white in the regular, which are both important to me in the color rendering of the fish and coral.
The light is going to be way more power than you'll need on a 15g tank, so you'll have plenty of headroom to dial in the look you like while still getting the power you need. I would start off with things dialed down and work up based what you plan to keep in there, coupled with (hopefully) PAR readings. Start with all the blue/violet/cyan channels at about 50%, red and green about 10% and then add white to your preference (probably around 20-25%). Then, if you need to, work up or down from there.
As for mounting, I'm assuming your tank is 15-16" wide, so I'd put the light a minimum of 8", probably 9" above the surface of the water to get nice even coverage.
