The XD300 is one bright, well built weapon light. The housing is solid and the light is good on battery life. I think it is a great unit.
That said, I am not a proponent of having a weapon mounted to your primary weapon.
I prefer to have a light in my off hand, with an on/off press light on the bottom like my Inova, but that is personal preference.
I don't like the idea of lasers either, as they point two ways when they are turned on. Again, personal preference.
I would prefer the ability to keep my weapon ready and in condition one, ready to go, and "strobe flash" with my off hand to illuminate what I consider to be a point of interest, instead of just highlighting everything as I make my way through the house.
Put the unit through it's paces and let me know what you think - I would be interested to hear a "range report".