Maybe I am worried for nothing and the upgrade from 4.1 to 5 will go smootly but I dont trust easy solution anymore.
Although the upgrade will usually go smooth, it's always a good idea to have backups!
Other than downgrading some of your CPU licenses in your My VMware portal, is to backup the VM's using Trilead's VM Explorer, which afaik is one of the few tools which works with the free Hypervisor.
André