Hello,
For any encryption you choose where vormetric, HighCloud Security, AFORE, TrueCrypt, etc. ensure your systems support the AESNI chipset functionality to offload encryption capabilities: Intel Westmere (some) and newer chipsets have this. If you do not encryption will use A LOT of your CPU.
Also note, encrypting in the VM has its own issues, you need to trust the administrator of your system does not know how to get the keys or in most cases if they can have the proper classification to see the data.
Best regards,
Edward L. Haletky