With the specs you mentioned, I'd consider to backup the VM's (in powered off state) and restore them on the new hosts. Unless you already have a backup solution in place to do this you may use e.g. VeeamZIP (http://www.veeam.com/de/free-vmware-esxi-backup.html). This way you not only migrate the VMs but also benefit from an up-to-date backup.
André