It is a great idea - the Pentacon Six is a good camera - often unreasonably maligned.
One problem is that the Kiev 60 is a copy (not a very close one) which shares the same mount and can therefore share lenses and also (with suitable mods and adapters) other parts as well.
The Kiev 60 is an awful camera, mainly due to poor quality control. There are now companies that buy them from the Arsenal factory and strip and rebuild. They are supposed to be much better, maybe even better than an old P6, but I've not tried one (My original Kiev 60 was a disaster!)
So... some of the Kiev 60 problems (film spacing, shutter problems) are often associated with the P6, without good reason. The P6 is much better engineered than the Kiev. Smaller and lighter, too.
My P6 has proved a much better camera and there are quite a few technicians out there (I recommend Rolf Dieter) who can repair and CLA them. Pentacon / Practica still do factory repairs, too, so it is still fully supported.
I agree with some of the criticisms by 'ath' - but you can buy a Kiev 60 prism and adaptor plate to fit the P6. The Kiev 60 prism is the best bit of the Kiev, it shows the full focusing screen of the P6, is brighter and has a meter. I have one - recommended.
Apart from that you have a cheap medium format camera that has access to a lot of very nice lenses. All of the Kiev 60 lenses will fit - as well as the Pentecon P6 lenses, The Carl Zeiss Sonnar 180, Biometar 120 and 80, Tessar 80 and the Flektagon 50 mm and some Meyer Gorlitz lenses, too. The Zeiss lenses are superb, the Ukrainian lenses are... sometimes good, sometimes 'interesting'.
There are, obviously, much better medium format cameras around, if you want to pay five times the price - but I reckon this is one of the best if you want access to good quality medium format optics for little money.
PS. If you have a Sonnar that is soft and dreamy... it is faulty!
