Bubby, there are lots of batteries out there and a lot of opinions as to whats the "best". Some like low cost lead acids like the everstart because you can swap them out on a whim in theory at any walmart. Some like more expensive lead acid batteries like a Trojan SCS because they perform well and last a long time. And some like the super expensive batteries like the optima sprial cell because they are virtually maint free.
My personal opinion, i fall into the "more expensive lead acid" catagory. I run the Trojan SCS series in my Z7 and i ran them in my 882 as well. The reason i like these batteries are simple. They offer a ton of bang for the buck in service time, reliability and power on the water. I have yet to find a battery that will give me the same or more time on the water then the scs 225's i run. They have also proven quite reliable with my last set going in my 882 some 6 years ago and were still good when i traded it last winter. I paid ~250 for the last set and to get that kind of life out of them as hard as i used them they were a great value in my opinion. Not to mention not having to deal with the constant issues i have had in the past with cheaper batteries. My new ones in the Z7 were 300 for the pair.
As far as the cheaper batteries go. I have a deep rooted hatred for any battery built by johnson controls(everstart, diehard, dura last, interstate,...). They have failed me too many times on the water and ruined too many weekends for me. I see a lot of guys tout the being able to go to any walmart to swap them out and thats great in theory. You have toi have a walmart near by and they have to have them in stock and you may have to deal with a pro-rate charge which can be quite a high percentage of the cost of a new battery depending on age. That warranty failed me more then once, i would rather spend the money on a quality battery that is far less likley to fail in the first place.
My opinion on the super expensive batteries like the AGM batteries or Optima's. I dont see where they are worth it. A few friends of mine run them in thier boats and i just dont see where the value is. They spent a great deal more then i did on my batteries * the optima is ~$250 a pop vs the $150 a pop i paid last year) and they dont get any extra on the water time(actually they get less) and they havent proven to last any longer from what i have seen. The only benefit i have seen is not having to put water in, in the 6 seasons i ran my last SCS 225's they needed water once.
Thats my opinion and i hope it helps. Compare whats out there and at the end of the day you need to buy what you are comfortable with and what fits your budget.