For me personally, the MT-G2 (dedomed) throws better because it lights up a bigger area as far as I can effectively see without the aid of magnification.
But, in absolute terms, the XM-L2 will probably beat the MT-G2 in any reflector to due to what Jerommel said above. I sometimes wonder if that would change if we could heat sink the MT-G2 enough to really crank up the amps.
Anyway, here are some MT-G@ throw measurements in various reflectors.