Airplane Batteries

I am a new airplane owner (since May). My mechanic replaced my battery
last June. No choices, I figured he bought the one it needed.

Just serviced it (added water). It's in a REALLY awkward spot to get at
and see inside the cells -- on the floor under the instrument panel of a
plane with no doors (climb in over the sides). I understand if the water
level is not just right, it will boil over and then needs to be cleaned
with baking soda and water. I've heard since that the battery should be
removed when servicing. Today I heard you can buy a dry battery, that
there is controversy about which lasts longer, but that maybe since mine
is so difficult to access, the dry type would be a better choice.

Thoughts/Opinions?