For this particular use case (i.e. "rare occasion when I need to run the off Windows-only application") I use a 4GB Windows instance in AWS. I only run it when

For this particular use case (i.e. "rare occasion when I need to run the off Windows-only application") I use a 4GB Windows instance in AWS. I only run it when I need it, in my case cost is negligible (in the $1/month range, Windows license inclided), launches a lot faster than VMware Fusion and best of all, my Mac is not slowed down considerably by VMWare Fusion VM image running.