2013 Kona Jake, 2008 Kona Major Jake, 2013 Kona Jake the Snake, 1999 Kona Muni Mula, 2012 Ridley Excalibur, 2008 Surly Long Haul Trucker
I've got a G2 on the front of my bike (with BB7 road caliper). It does OK and looks nice enough, but it squeals like mad after a fresh rain. I suspect that most (if not all) rotors would. If the price isn't too much more, I'd probably try the HS1 just to see if it's any better.
I have the g2's with avid bb7's on my crux (cyclocross bike) and they work great, I think they are 140 and 160mm rotors. However from what I have read it might be smart to double check that the rotor you are considering is compatible/recommended for use with your brake model as such things can lead to catastrophic failure and injury.