Nothing wrong with buying a clapped out GII, just budget for lots of fuel and money in spare parts and plan on throwing it away in a few years. As it is a buyers market, the higher value airframes depreciate, so run the numbers, as long as the extra cost in fuel and parts outweigh the depreciation and the smaller cost of operating a newer airframe, go for it.
Keep in mind, it will never be cheaper than flying business class and plan to be severely limited in Europe if you do want to take it over here due to noise. Plenty of US airports have noise restrictions too.