My serious entry to MF was the Mat124. I wanted to see if MF was for me, did I like the negsize and the square, did I like to use the WF and the handling of the camera and last how did I perform with those negs and the glasscarrier in the darkroom. I don't regret it though the mat is almost exclusively used with IR-film since I met my Zenzei (Bronica).
Reason for buying the Bronica. Being used to SLR and close up photography I have a hard time getting used to not seeing precisely whats getting on the pic. I felt I needed the ability to change lens/focal lenght. I wanted a system camera.
The Yashica is lighter than the Bronica and I think a tiny bit smaller. It is very easy to use and makes great pictures. Now when I have both the drawbacks of the TLR ain't as anoying as I thought at first. A good specimen of all the recomended TLRs will take you far in MF before you need more.