3/8 or 1/2 Impact Wrench?

Need some guidance. 3/8 or 1/2 in Impact Wrench.

Which is more practical for a DIY home mechanic. Throughout the year tire rotations and work on the car such as brakes and suspension etc. Any pros/cons with the socket attachments etc...

Also do the Hercules batteries work in Bauer tools? I have the Bauer cordless shopvac and tire inflator tools. Would want the Hercules battery to work on those tools as well.

Looking at the Hercules bundle battery and tool bundle deal for $99. Gonna stack on the 25$ off coupon.