Well I had a 900 several years ago with the standard head and the turbo head.
My opinion over time of use was that it was oversized, overweight, and just plain bulky and didn't balance that well. It seemed like a great concept when I bought it but in the end I eventually sold it or traded it off on something and since then I've used X300's, M600's, and M300's and I prefer all of these compact, lighter weight, options to the 900 series.
The only thing I miss about the light is the Navigation lights on it. I really liked that feature quite well.
"Colts and Kimbers are what you show your friends. Glocks and HK's are what you show your enemies."
Sig Sauer LE Armorer
Glock LE Armorer
Colt AR15/M16 Armorer
T.O.S.S. (Tactical Officer Survival School) inst. Tom Long
Vicker's Tactical Pistol 1 & 2 inst. Larry Vickers
Vicker's Carbine 1 inst. Larry Vickers