This got me intrigued, so I went to Guitar Center for lunch and played with one for an hour....
1.) They would not let me disassemble the VG, but it appears as if a normal S-S-H routing has been extended downward just a little; on the back there is a removable battery pack (has to be, eats a set every 10 hours) to the right and parallel to the top of the tremelo cover; there is a large additional cover plate over a routing slightly wider than the tremelo cover that extends almost to the guitar's bottom edge.
2.) In "normal" mode, no real difference at all from an alder American Std. Strat played through a Fender SuperSonic, except tone control for neck/mid pickup is single pot.
3.) The upper "effects" rotary control has the alternative tunings + the 12 string setting. I don't really use alt tunings, but the effect sounded okay; I WAS impressed by the 12 string emulation. I was expecting these features to sound more "electronic", but they are pretty natural sounding.
4.) The lower effects knob lets you switch between acoustic - Strat - Tele - Humbucker modes. The acoustic mode is just okay, sounds acoustic like a lower end Ovation, nothing great. The Strat/Tele/Humbucker modes sound passable, but all three modes while sounding like they're named emulate bridge pickups and sound a little "treblely"; if you try to back off the treble with the master tone control you lose some of the sound definition.
If you look at the product reviews on the VG, there doesn't appear to be a lot of middle ground, people either love them or return them. If you use a lot of different tunings in a set and/or play through heavy effects some of the dings I pointed would be so noticable, but again you could get a lot more/different functionality going with a Variax or using a top mounting Roland GK-3 and the VG-99 floor unit the VG's electronics are a subset.
I'd pass on this right now myself, but check it out, might be your cup of tea....