I have 3 of them
20Ah for spotlight hunting
one for my Suzuki 200SE Trojan AG bike.
one in my mum's Yamaha Bruin 350 Quad.
The spotlighting ans Suzuki battery are in the box and only used when needed so they dont get flat. had them for 3 years now and they just work.
the Yamaha Quad battery is left in the quad and it only gets ridden for a week every 2 months. It has not missed a beat and every 6-12 moths that I get to the farm I goto recharge it and it has been always fully charged even after sitting for a few months.
Motobatt offer quad post batteries - these are good when you need to add extra farkles and you can use other battery post.