if you're racing and want the option to switch out spare batteries, this makes a lot of sense. I'm just trying to extend my post-work mtb rides until the snow stops me. i figure that the taz 1200 from light and motion will fit the bill.
this light is very powerful and the price was unbeatable, but mounting the battery to my mountain bike (Yeti SB-66) was time consuming and frustrating. it seemed like no matter how tight I got the strap on my top tube or bottom tube, it would still slip. Also annoying is the excess cable length.
overall, a good quality product that seems to be more of a racer's light. for those of us just trying to extend our fall rides an hour or two, i wouldn't recommend this.
I have the light and motion viz 320 plus which is an amazing light combo. i'm excited to buy the taz 1200 to compliment it. after each ride just plug both of them into my computers USB ports for tomorrow's trail time