Significant differences in quality usually are associated with the purity and type of lead used for the plates, either AGM or some sort of "starved" electrolyte. There is some special magik to the alloy/creation of the lead that increases the porosity of the surface, in effect increasing the surface area available for the electrolyte. Some batteries are better than others in this aspect.
The connection of the plates within each cell and across each cell to make it into a "battery" are different between high and low quality batteries. Also the size and quality of the terminals on the exterior. All you have to do is compare a WalyWorld battery terminals to a Odyessy, Braille or even the Yuasa (they are typically "top shelf quality) to see the difference.
another way to compare batteries, provided that the case is made in a similar way and material and they are of similar dimension, is weight. Basically, more LEAD equals more capacity/ability to do work and therefore will weigh more. Of course this is not completely fair because of what I pointed out previously regarding all the other stuff....
Aint this fuN?