Simulators for practicing Cisco's CCNP routing and switching exam

Simulators for the CCNP exams are not very prevalent today. If I had to choose one for myself for taking the routing and switching exams, I would go with Boson's Netsim. It has some pretty advanced CCNP features in it and comes with predesigned labs. The downfall is that the environment in which you can practice commands and set up custom lab scenarios is generally limited. Plus, it is difficult to simulate troubleshooting which is integral to passing the routing and switching exams.

If your budget allows, I would consider possibly taking a training class for these exams as they are generally the most difficult to pass in the CCNP track.