I own 505-2 (belt drive, 1984), 506 (belt drive, 1980), and 1228 (idler drive 1974). Also previously a 515 (belt drive 1986) and 721 (direct drive, 1977).
Avoid the ones with the plastic bases.
505-2 was the giant killer budget table back in the 1980s. Use with an Ortofon OM10 or Nagaoka MP11/110 and you'll have a very nice deck for little money. Older idler drive models sound great too. Our direct drive 721 sounded great but they are hard to get serviced.
Duals are good but a Rega or high quality Japanese direct drive may sound better.