Advice on best 6v battery brand?

I never got to try to Optima 6 volt because I changed over the 12 volt in my car. But, whether it was problems with my car, just letting it sit too long, etc. it seemed to eat up all the 6 volt ones I was buying...to the tune of 1 a year. Either way the Optima 12 volt has been good to me in all my cars. Not sure if it is the same on the 6 volt but if you do let the thing decharge (lights left on, etc.) all the way you need a dry cell charger to bring it back...the regular old chargers I had wouldn't recognize the battery was even there...

 

Go here: http://www.battery-usa.com/catalog.htm and click on Automotive Battery Selection.
They show both 6 and 8 V batteries.
Johnson Controls makes lots of the batteries sold in the USA under various names.