We have an S and a 6 seater X. When we need to carry anything we use the S. The X does not hold nearly as much with the weird shaped area to try and put things with the middle seats scooted forward. Unless by versatility you mean carrying more people, I think the fold flat ability of the 5 seat configuration gives it the most flexibility to carry “stuff”.
I hear you, Firewired. But... doesn't the new "fold-flat" 7-seater offer the same flexibility to carry stuff as the 5-seater??