I highly recommend the Everstart batts, been using them for many years in all of my boats and vehicles. Just pulled a 24MS from my little skiff, 1 cell went bad. Could complain, but the born on date was 5/13. Had a pair of their Maxx 29s on a 24v troller that lasted 5 years, have a 3 yr old Maxx 29 on my current 12v that's going on 3 years and in excellent shape.
yes Johnson Controls makes most of the wet cells sold in the U S under many brand names: Everstart,Autozone,Interstate,Die Hard, Pep Boys,Motorcraft to name a few. Be aware tho that JC offers several levels of performance within each group size, check the specs carefully. Bottom line, a heavier wet cell within any group size will have better specs.
Caution on the Batteries Plus Duracells, they import a lot of China made AGMs while Sams sells the Deka USA made batts(same as the Deka Intimidator,highly rated) - read the label for country of origin.
Never pick a batt with a date code over 2 months old, Wal-Mart turns them over so quickly that it's rarely a problem there. And there's Wal-Mart's every where, easy to go to another store if the one you're in doesn t have the model you want.
More important tha n what battery you choose is your recharging system and habits. The faster a drawn down battery gets recharged the more capacity it will retain and the longer service life of will have. Period.
If you have a boat with a 20hp, you don't need more than a group 24, the extra weight will get you no advantage.