To be honest it depends on the VMs. Windows 2008R2 VMs seem to run fine with SnapDrive 6.2, 6.2P1, and 6.2.1....all tested with FC RDMs. For Windows 2003 R2 x64...SnapDrive 6.2 does not work with vSphere 4.1. You will have LUN enumeration errors because the initiator is not supported. You must upgrade to 6.3P1 for it to work.
http://now.netapp.com/NOW/download/software/snapdrive_win/6.3P1/
By the way...the SnapDrive service startup in this config is now CONSIDERABLY faster...damn near instantaneous.