They're both pretty different shoes.
On one hand you've got the Barricade III, which is a tank of a shoe. Heavy side, lots of cushioning, lots of stability, all that.
On the other hand, you've got the Vapor III, which is a ghost of a shoe. Lighter side, minimal cushioning and all that.
However, Vapor III's are pretty bad for what they're designed for: a speed shoe
While the Barricade does exactly what it's designed for: a beefy hardcourt shoe for the serious player.