Take it from a guy whose made a living the last four years finding answers to these exact questions (Owner/Operator of Batteries Plus Franchise)...Certain brands are VERY proud of themselves, ie: DieHard, Optima, and yep, YUASA.
I've found no performance gain to justify their prices. In fact, I've sold countless batteries to replace Yuasas to riders pissed that they spent that kind of money last time.
CCA, as I discovered in an earlier post on this thread, is mildly important when looking at these very similar batteries. Brand is all about marketing. What makes a MUCH bigger difference in your batteries performance is how you take care of it, and what conditions it is subjected to. Don't run it dead if your bike won't start. Keep it charged as frequently as possible (merely riding will do this). Or keep it on a Battery Tender
for storage. Lots of vibration, very hot or very cold conditions will severely excellerate wear on your battery.
Currently I've got the DRZ 7BBS battery in my airbox made by God knows who in China. Works excellent. Always has. I am very satisfied. Never buy "reconditioned" or "rebuilt" and get one locally so you can get it warrantied if you need to. Be good to your battery and what sticker they slapped on there with whatever specs they throw together will be irrelevant.