Fantastic decks, and you would probably need to spend not far short of £1,000 (minus arm) to get a modern new deck of similar quality. In fact the reborn Thorens current 160 deck is a lot more than that. Of course while Linn got all the (UK) hifi plaudits, the Germans had been using similar sprung-chassis designs quietly for many years before. At the time their only real weakness was the own-brand arms (they weren't bad, just not up there with things like the SME). So a 160s and a SME 3009 - damn near perfect I would say.
Things to be aware of? Well the decks themselves are very easy to diy adjust, level, service and fix. New OEM belts are cheap, while if anything major went wrong a motor swap would be very cheap given all the spares floating around on ebay. They are also easy to tweek (plenty of ready made componants and kits of you do a search, although things like a new better/stiffer bottom base board and feet are very easy to diy from scratch.
As for the 3009 arm you should look out for knife-edge bearing problems, and given their age a re-wire (improved with continuous rather than the original joint) is often a good upgrade (unless you want completely original classic), which is a diy possible but I would rather trust one of the small specialist companies out there to do it.