Ryobi batteries are cheap comparred to others as well. You don't have much opinion on the tool longevity though? Sounds like you would prefer Ryobi of Craftsman?
I don't know if it makes a difference but Craftsman's 20V lithium ion is in their "Professional" line which I was once told they were built better and more durable.
The Milwaukee looks very nice, however, I cannot find it cheaper than $450 + Shipping. I'm afraid that is more than I should spend. If you know of a cheaper supplier please let me know, I really like those.
Milwaukee Electric Tool - 0920-29, V18™ 4-Piece Combo Kit, Cordless Combo Kits, Cordless Combo Kits, Tools