This is right from Checkpoints site. This only controls the failover and state. You still need to have the cluster of two or more gateways. We have 1 management server and 2 Nokia Boxes using VRRP as the clustering method. Hope this helps.
ClusterXL
High Availability and Load Sharing for VPN-1
ClusterXL is a software-based load sharing and high availability solution for Check Point gateway deployments. It distributes traffic between clusters of redundant gateways so that the computing capacity of multiple machines may be combined to increase total throughput. In the event that any individual gateway becomes unreachable, all connections are re-directed to a designated backup without interruption. Tight integration Check Point management and enforcement point solutions ensures that ClusterXL deployment is a simple task for FireWall-1, VPN-1, and FloodGate-1 administrators.