That 231c looks very similar to a MAC tools impact that I've had for 20 yrs, great gun.
Its being collecting dust for the last several years cause I bought an IR 235 titanium, I think the newest model is 2135.
The titanium models hit way harder weigh less, awesome guns. I would also look at the stubby impacts, some even have higher number than what that 231c will have.
I've never owned any HF air tools but I know guys that have and from a professional standpoint they won't last. One guy would have his HF die grinders fail every 1-2 weeks, come borrow mine then say how stupid I was for owning MAC, Snap on etc branded stuff.
IMG_3958 by
eric2406, on Flickr