Thanks Shane,
Yes, I saw the prices but rebuilt prices to upgrade to NiMH are pretty cheap, $45 and $57 for the 12 and 15.6v NiMH as opposed to $60 and $115 for Festool.
I'll likely go Festool for the 12v packs because of the competitive pricing.
I'm still interested in anyone who used a place like MTOBattery.com (they get quite good reviews)