How much should I pay for synthetic ATF?

I'm going to drop the pan and flush my system and put in a synthetic, either Mobil 1 or Amsoil. The cheapest prices I found were:

$6/quart for Mobil 1 at Autobarn
and
$7.70/quart for Amsoil at their website

Is Amsoil worth the extra $1.70/quart?
Is $6/quart a good price on Mobil?

Also, will a case of 12 quarts suffice for a flush? Thanks

 

AMSOIL is definitely worth the extra few pennies.

 

$5 at auto zone for mobil 1

 

12 Qt. is enough for a flush. You can get Amsoil ATF from Talkinghorse for a good price (see Group Deal forum) or Mobil 1 ($5) from Autozone.

 

If autozone sells Mobil 1 for $5/quart (thanks NYC TAR) then Amsoil becomes about $30 more expensive for a case of 12. That's an extra 3000 pennies, and I like to keep my penny jar full. Is Amsoil really that much better?