the 600se is not at all a mamiya 23. it's near to the mamiya universal, which is quite a difference. there are 2 websites which will tell you all about it. the one for the 600se is here:

http://filmwasters.com/forum/index.php?topic=779.0

and the one which tells you the difference between the mamiya universal and the 600se is here:

http://moominsean.blogspot.com/2010/...oid-600se.html

read through it and come back if there are more questions.

reinhard