I think the second is the best option VMware KB: Exporting virtual machines from VMware Workstation to ESX/ESXi
As you can see you can export the VM and after import on the EXS (Do not use customization)
But uf you have Vmware Workstation 8 or higer you can connect it to the ESX server and move the machine. If you are in the same lan and do it in a low workload time it would be the best option.