GroupWise 8 to 2014 Hardware/OS/Software Upgrade

I have been running GroupWise 8 in an OES2 Cluster configuration for many years. Before that GroupWise 7 in a Netware Cluster. I plan on upgrading to GW2014 this winter and contemplating two different solutions:
OES11 Cluster on physical servers with GW2014 or SLES11 in VMware with GW2014. The OES11 solution would be a rolling OS/Cluster upgrade and then GroupWise upgrade which with it a lot of planning and testing and complexity, but once running is a very good HA/DR and easy to manage system. VMware SLES solution would mean building multiple SLES guests loading GW2014 and migrating data from NSS to EXT3. Simple configuration, and I would then rely on HA from GroupWise Monitor, and DR from VMware.

What are companies doing these days for maximum HA/DR with GroupWise? Is there a question about performance in VMware? Is there a definitive Linux filesystem of choice?

Thanks in advance.