batteries are deceptively simple to make...
more plates=lower ESR and higher current abilities
when used in conjunction with virgin lead and AGM, you get more current AND higher reserve.
and thats it basically. theres no fine tuning, no exotic compounds or anything. Unless you want a carbon fiber case, or a lithium battery (big money), that about all you can do to improve a battery. Luckily, that means that a "discount" shuriken battery can perform damn close to the same level as a comprable size kinetik or xs power. At the end of the day, most companies take a core from hawker/enersys, throw it in a case, slap a sticker on it,, and sell it as their own. These cores arent made by powermaster or kinetik or whoever, theyre mass produced and then just stuck into cases.
Moral of the story:they may not be exactly the same, but they will all be remarkably close. when people argue over xspower being better than kinetik, theyre talking about marginal differences.