[MatthewS]

With so many visio shapes, I would stick with Visio (for now)

Even though technically OG can open visio files, it isn't 1:1 conversion. OG does a pretty good job as far as non-native importing is concerned, but if you've got a pile of .vss files (and you need to keep them as separate assets) you're pretty much stuck with Visio.

You need to get all that stuff into an OG native format before you'll see some performance improvements.