Please can you offer your valued opinions as to which medium format camera I should buy, it's my first one. I am an amateur, post grad student and the work I make needs to reach professional standard. I want to buy one with a Polaroid Back. I also need your advice on what lens to look for. Budget is a huge issue as very limited and I will buy on Ebay. Many thanks
You write "the work I make needs to reach professional standard".
That has nothing to do with the camera format you select. Nor does it have anything to do with film versus digital.
Tiger Woods can beat you at golf using a shovel. Don't equate camera selection with professional results. A shaky, poorly composed large format landscape is worse than a sharp well composed camera phone shot.
If medium format is the road you want to take, all of the brands are good. Bronica, Mamiya, Hassy, Rollei, Pentax, even my auto everything Fuji, were all aimed at working pro's, and will all render, in the right hands, great pictures.
Best of luck on your hunt and purchase!