For my personal use on the off chance I can't find something here lying around the shop that still can kick one over, I won't buy batteries from Vato Zone anymore (Yeah I got a dud once, so LOL dunno why but I don't!) but I do still buy batteries from Wal-Mart.
For those skis with the teency-weeny-dinky batteries, I think you can't go wrong with the correct YUASA battery your ski came with from the factory.
A lot of guys claim they like their glass mat AGM type batteries, I'm not convinced they can outlast an undamaged wet type lead acid though. Operative word is undamaged.
Personally, I've had as many dud batteries from about everywhere I've come to the conclusion it doesn't matter where they come from as long as they've been handled properly. The battery guy that delivers new ones to the marina here freekin' tosses those things like luggage and I'm not impressed.