RDM is needed for guest clusting and to speed up a P2V when the data are already in the same SAN.
In other cases a vmdk is a better choice.
1 person found this helpful
I agree with Andre. In most case it's best to keep it as simple as possible and that means using VMDK unless you have a specific use case that dictates other wise. There are also a ton of post and documents regarding this same question if you want do to a few searches.
If you found this or any other post helpful please consider the use of the Helpful/Correct buttons to award points