Milwaukee M18 Fuel or Ingersoll Rand 20v would be my picks with the advantage going to the IR for being a bit more balanced. Neither is quite to the point of being an air tool replacement comfort waise. Power wise they compete though but they are still bulky unlike the 3/8" models which have essentially replaced my air tools in that size. I don't use my 1/2" air gun anymore because its nicer being cordless, but if you have a lot of work to do in a day the air gun is still nicer.