Based on a review, I bought a Hitachi 14.4 Li impact driver back in 2008. The review suggested that the 18V drivers (at the time remember) were more for the deck builder, etc. Prior to this, I had shied away from Hitachi because to me they look more like athletic shoes than serious tools.
Though I am not a contractor the drill has seen serious use and while not "for the deck builder", I have driven alot of three inch plus screws into SYP and PT wood. This tool is more often than not my go to tool for alot of jobs. Plus, I am still on the original set of batteries (knock on wood).
The only thing I would say about breakage or spin out is that with phillips heads, you need to use more pressure. Torx heads are best. Square heads seem to stick a bit when I go to pull the bit out of the screw but I still use them if I cannot get the torx in the size I want.