I think that by the time you will be in the market for either battery the price will have come down greatly. Why? Because over the next five or six years when that 12 volter is likely to be replaced there will be aftermarket replacements. Other car companies are already commiting to the Toyota HSD system (Ford, Nissan) and more are likely to do so. More hybrids on ther road will tranlate to lower costs for the HV batteries too.

I'm not a marketing expert or an automotive engineer, but I did stay at a Holiday Inn last night.