The G8 is a rebadged Holden Commodore from Australia.(http://en.wikipedia.org/wiki/Holden_Commodore). Holden also built the 04-06 Pontiac GTO (which is a rebadged Holden Monaro) and provided the engineering work for the new Camaro, although the Camaro will be built in Canada and not in Australia like the G8 and GTO. The GTO is an excellent car and is very similar the the G8 (I own an 04 GTO, it is excellent).
The G8 interior is very good quality, the engine is very powerful (361 HP in the GT, 415 HP for the GXP with the LS3 Corvette engine), even the LS3 will get pretty good gas milage with the 6-speed manual transmission. Rear wheel drive is a big plus in my book, although it is far from being the only quality RWD car on the market. Most importantly the value for the money is pretty much unbeatable, it has performance rivaling the ~$80k M5 for about half in GXP trim. I think the styling is excellent also, although I also love the 04 GTO's looks which many people didnt.
The problem is that it probably wont sell terribly well despite being an excellent car which means parts will be fairly scarce in the US. The aftermarket will be expensive and spare parts will need to come from Australia. It could be a bit tricky in the snow, but that's nothing a set of good snow tires (i.e. Bridgestone Blizzaks) can't deal with. Be prepared for a pretty big car, although you should be expecting that if you are buying a full sized performance sedan.
