I don't know about "best tank they sell" - I really think, as someone else said, that most of the bladder-type tanks from any of the major manufacturers are pretty close in quality.

It looks like 119 gallons is the biggest Well-rite (Smart Tank). Note that the size rating of a tank (119 Gal) is significantly more than it's drawdown capacity (i.e. how much water you can draw before the pump kicks on. This Link has the specs.