A measure of what makes a battery superior.
I am fairly certain all the "replacement" batteries listed have almost identical technology in the chemical storage. As Head2Wind points out the maintenance of a battery probably influences the performance a heck of a lot more than the incremental differences between each battery available for replacement in your KTM.
What appears obviously different between them is:
Weight, size, cell capacity, package material and quality.
The WPZ14S is 9.8 lbs compared to the 5.9 lbs of the PC310 from Odyssey.
Immediately, I would think the weight differences certainly suggest the ability of a manufacturer to contain more electrolyte and electrode material in a given package. So,... it makes sense that the PC310 does not offer as much capacity, reserve, or CCA compared to the others. But that doesn't make it a bad battery. It is what it is.
To me, taking everything into consideration, the nicest, most efficiently packaged battery appears to be the B106... but by a negligible margin. And for what is readily available in the product literature, the stock battery electrical specs are as good as any, especially discharge capacity. Obviously Braille provides many additional electrical specifications to persuade people to purchase the product, hopefully based on verifiable tests. Like I said, the Braille product looks, smells, and performs good.
If we were to have all of the PCA, or other electric spec data for the other manufacturers, the picture perfect battery may be as confusing as ever. As mentioned by other people, the only electrical rating standard that seems to be readily available for each battery is CCA at 0 deg F. And all of them are equitable at between 200 and 250 CCA except the PC310.
However, I think that most of us agree that the CCA rating is useful, but does not describe battery discharge efficiency for real world parameters.
Theoretically, a battery should provide the same amount of energy regardless of the discharge rate, but in reality... internal energy losses cause the efficiency of a battery to vary at different discharge rates and temperatures. Perhaps in this respect one could consider battery fatigue as an indicator of battery quality/ durability. Example: PCA at 30 seconds @ 0 deg F... While another person might only look at the 5 second data @ 80 deg F as a litmus. After all, who is starting the bike for 30 seconds.
"If you build it,... they will come"