I've only been using the Huge for a week or so and I'm really loving it. The padding and size are just right for my (admittedly small) hands, but the best part of all is that there are TONS of buttons, which can all be re-aliased.

The only down sides I've run into so far are:

1. It's a bit clicky

2. The wheel being thumb-driven is a bit awkward for me

The utility I'm using (SteerMouse) sadly doesn't seem to properly support chording for using the trackball for scrolling, but I've contacted the dev about that and if he can get it working, then I'll be 100% happy with this.

If you can find a Huge at a decent price (they're ~$37 USD here in Japan), I'd highly recommend giving it a shot. The Ploopy seems like a far worse deal in comparison to me (though I don't have the nostalgia connection) at $200 CAD.