I've had the best and most expensive batteries take a crap. I have had the cheapest batteries last for years. I'm not convinced there is a whole lot of difference in a lead/acid batteries.
I think some of the keys to good battery life are;
1. Keep the battery and the terminals clean.
2. Keep the acid/water levels up. (At least check the levels before charging or storing on a battery tender)
3. Keep the battery in service. Use it.
4. Have battery tenders on them when not in use.
5. Keep the battery tied down when in use. Don't let them bounce around in the battery holder.
