I use my Surefire G2 LED as my daily carry torch, and after reading the reviews for the Fenix TK10, I must say I am impressed.
If your planning on using it as a weapon light, I recommend the, Viking Tactics light mount:
http://www.vikingtactics.com/prod_vtac_lightmount.html
Light-weight polymer that gives you that offset to use on a rail with a vertical foregrip. Seriously think were you want to mount the torch. Remember to mount the torch as far forward as possible. This way if a BG (Bad Guy) sees the light and engages you from the side, its farther away from your body. Moreover, if you mount the torch too far back the weapon will cast a shadow, placing the torch on the bottom will cause the barrel or fore-end to cast a shadow over the BG's eyes, negating the effectiveness of the torch. You might be good to go, but if your running a suppressor don't forget to reposition the torch to adjust for the increase in length.
Just a few tips, to help anyone out when they encounter any low-light fighting.