To me its what other cordless tools you have or will buy. I try and avoid any cordless tool that requires a unique battery and charger.
My guess is the Milwaukee M18 Fuel is equal to the IR, or pretty drn close.
2015 Subaru Forester 2.5 engine/CVT
2015 Ford F250 w/Powerstroke
2016 Subaru Crosstrek CVT (wife's)