no one spoke of disadvantages - Rodinal, the mind-enhancing drug of the 21. century!
Now I´m gonna smoke a Mommsem....
Tony, at the price you are willing to pay you may get a decent early Zorki4 model from Oleg, serviced and CLA´d... he (www.okvintagecamera.com) has the best fame in the SovRFKam community (which is very avid at http://www.beststuff.com/forum/list.php?f=21).
I prefer the early Zorki4 over a 4k (I have a 3S... beautiful thing) for it´s sturdier built quality and the transport knob, I don´t need a lever wind.
With any Zorkii you´ll get a Jupiter8 lens - those are Sonnar-siblings, deriving from the Contax-Sonnars.