Whilst shopping for a cordless drill/driver I was impressed with how small the cordless impact drivers were and yet deliever about twice the torque of the larger cordless drill/drivers.
Can impact drivers drill alright? A few on the web talk as if it's morally wrong to drill with an impact driver, but never cite the chapter and verse.
Makita makes adapters going from 1/4" hex shank to keyless 3/8 chuck, so if you want to use your normal round shank drill bits, you can.
I know an impact driver is noisier. That's OK with me. I know an impact driver can be slower. That's OK with me. Any other drawbacks?
I work with wood, concrete and steel, but 90% of the time it's wood.
--zeb