It depends on how you are going to use your batteries
For storing the most available electricity for your use the deep cycle lead acid battery is still the best. I used two huge T-105 Trojan 6 volt golf cart style batteries for years.
http://www.altestore.com/store/Deep.../p1771/?gclid=CPLk_8qet68CFQ4zhwodADoCiQ They were hooked in series to yield 12 volts. I could go to Lake Powell and use them daily for up to 10 days without a charge. When it came to charging them even after a weekend it would take at least 20-30 hrs. Had to keep the electrolyte topped off and they were somewhat messy and very very heavy.
More recently I switched to batteries that suit my new situation which allows me to charge up after every day's useage. I chose a Deka deep cycle AGM battery called the intimidator, model is 8A31DTM. Two are hooked up in series to yield the 24 volts required for my 80 ft/lb thrust Minn Kota bow mount with an optimizer. The beauty of these batteries is they aren't messy are not so huge and charge up in 3-5 hrs even when drained to down to 35%. They also hold a charge a long time when not in use. It is important to use a AGM rated charger and Schumaker makes several that are even carried by Wal-mart for around $50.
I understand Deka has improved their line up of marine deep cycles to include a gel that is called the dominator with even more power. Link showing latest offerings of marine deep cycle and even dual crank/deep cycle batteries.
http://www.dekabatteries.com/assets/base/0181.pdf Need power for days? Go huge deep cycle lead acid batteries. Power for a day? IMO go AGM or gel deep cycle.
Hope this helps
