The monarch is very fast and the One is very slow. If you take a short agressive approach the One will pop better and if you use a smoother more progressive approach the Monarch is a better fit. The monarch sits high in the water and is very loose. The One, especially with 1" fins says pretty locked-in.
The ATR is a nice option. Even if you only hit rails very rarely.
They are really for two different types of rider.