I've had good luck with Deka batteries, the newer Noco stuff is awesome and light. Quick story on a Noco (NLP14) un related to jet skis.
My buddy and I were in the middle of the desert riding our KTM 890's, big enduro bike. He had recently replaced his battery with a Noco lithium. Bike started no problem all day, cranked really fast. He stalled the bike one time coming out of a sand wash. Check engine light (read code and 12V low) and totally dead on power, ignition switch had no affect on turning bike on.
We had to remove my battery and hold it against his noco lithium to "wake" the battery up. after that it was fine the rest of the day. To me thats a little scary, if this happened on a ski it would be a way bigger deal as your trying to jump start it with the hood off floating, etc.