While there are many different "brands" of batteries (Sears, Kirkland, Napa, Motorcraft, Interstate, etc...) these are just rebadged batteries made by just three manufacturers in the US (who knows what's coming from China). Here is an unverified source that explains who is making who's batteries...
http://www.answers.com/Q/Who_makes_car_batteries_in_US
The majority of car batteries are created by 3 manufacturers - Delphi, Exide and Johnson Controls Industries. Delphi makes some EverStart models sold in Walmart and ACDelco. Johnson Control Industries makes Duralast seen in Autozone stores, Diehard - sold in Sears, Kirkland - the Costco brand, Motorcraft - which Ford sells, some of the EverStarts, and Interstate. Exide makes Exide batteries, Champion, Napa and even a % of the EverStart batteries.
I have a pair of Optima's in my truck only because the previous owner put them there. They are good batteries for sure but I'm not married to them. Their cost being what it is and need two would mean I will probably end up with a pair of Kirkland batteries next time around. Costco seems to still have a good return program with their batteries, the warranties may not be as long as they used to be or as generous as they once were but if the battery does prematurely fail they generally take care of you pretty well. And let's be honest, the fact that any battery can last under the hood of a car for more than 36months in the thermal cycles it has to endure is a testament to good engineering.