Dual 704 turntable. Any good?

Could anyone out there shed a little light on the merits or otherwise of a Dual 704 turntable and a Technics SP 12? I have the opportunity to buy either but I do not know which one to go for. Its my intention to seriously mod-up whichever deck I go for by having new plinths made of granite/plywood and also to fit a high quality arm, in the region of £500 to £800 price range. Be very handy if I could get some feedback on whether it is a good idea or not or if the decks in question are worth spending the considerable money such modification upgrades would cost. Any advice would be very welcome.