Originally Posted by Max Power
I would go for the Mamiya as you will get super quality + versility at affordable prices. I progressed from fixed lens TLRs to the Mamiya TLRs for those very reasons. I mentioned the weight as if you want to shoot colour and mono you will need a two body + a few lenses outfit (eventually). Also I found a heivier tripod was needed for the Mamiyas whereas I could get away with a lighter tripod with the smaller TLRs. Weight is more of an issue for me these days as I am now 60+ and although still quite active I do watch what I carry on my back! If you decide on the Mamiya I would recommend you try to handle one before buying to make sure you like the handling etc. I found the Mamiyas a joy to own and use, they slow you down and make you think about composition and metering. And that can't be a bad thing!
All the best,