Boat Batteries ...

[Mac Attack]

Which battery last longer ?  One with float charge a 2 amps, or float charge at 12 amps ?

Neither really - the float charger reduces amps as the batter reaches full charge to protect the batteries plates from overheating and warpage.
It will only provide to the battery what is needed.
The 12 amp unit will charge a low battery back up to full charge quicker than the 2 amp.
So if you need your batteries charged quicker get the 12 amp unit.

[Beets]

Have been using Minnkotas for 20 years and have had reliable service. Some friends also use Everlast and had good luck. I can get a battery to last 7-10 yrs so far.
I put it on the trickle charger every time I get home from fishing and leave it on til I go the next time.
 I leave it on all winter.
Tight Lines

[3300]

Beets
i do the same thing and for the same amount of time. the charger must be 20 years old too and works great. it pulse charges and is for deep cycle.
i noticed a large increase in run times after buying it back in the day.