I think you should be careful about VI One. The sounds are great (according to the demos), but it isn't merely a GM module. In fact, the GM section looks pretty weak to me.

From the manual:

"The General MIDI is a highly compacted and optimized General MIDI bank featuring the 128 standard
GM instruments plus 8 GM kits. The entire bank totals only 32MB in size, so is very quick to
load and is intended for quick MIDI mockups."

So, if you want to spend the time to assign each MIDI track to a VI One instrument, you'll get great sound. But I doubt their 32mb GM subset sounds any better than the other GM softsynths mentioned here.

If you want a good GM module, I'd recommend using hardware. And the Ketron SD2 is the best currently produced one I've found (I own two).

I also have Key Rig, though I never used its GM module. But it is handy for live playing on a laptop when you want a large assortment of sounds in a small system resources footprint. It has some nice pianos, eps, organs, and synths, all of which sound fine in a live (MIDI backup) mix. Not so good for solo piano work.

Dave Burns
Lowell, MA