Battery Question for Broad Knowledge ....

Dedicated to this site for 6 years I've read various battery Strategies.
I'm getting ready to purchase (4) 6 volt house batteries.
Asking because I don't know: what makes one batt better than another?
There aren't that many parts!!!
Is it the quality of lead or acid? The amount of lead? Can't be the terminals, case or access caps!!!
Just asking so I can get smart!!!!