I have looked through older threads and am seriously considering a Craftsman C3 cordless 1/2" impact wrench. Not the best but good enough.
Generally the DiHard NiCads are easier to find, much cheaper, and have typical NiCCad problems. DiHard Lithium batteries seem to be hard to find and the reviews are not that good.
I consider this tool more of a emergency use tool and will not routinely use it.
Considering the latter, need battery recommendations and overall agreement with approach vice Craftsman bashing...