I have had experience of a number of TLRs in my time.
a) Yashicamat. I had an early model. It was quite nice to use (everything worked as it should). The lens was sharp but nothing startling. If I remember correctly the focussing screen was not that bright but by no means difficult to use.
b) Minolta Autocord. A definite step up from the Yashicamat. A lens that was noticeably sharper and more contrasty. It had a quirky loading system in that you loaded it from the top down rather than the traditional bottom up. I enjoyed using this camera a lot.
c) Rolleicord (cant remember which model). A very nice camera with a lens (if memory serves) that was every bit as good as the Minolta. Very easy to use.
d) Mamiyaflex C2. Had a film transport mechanism that was prone to wearing out quickly which caused film spacing issues. Lens was sharp and contrasty. I would not recommend going for one of these due to the film transport issues. Spares now unavailable.
e) Mamiyaflex C220. A much better camera that the C2. Silky smooth controls and lens interchangeability a real boon.
One word of warning about the Mamiya range of lenses. Don't buy the chrome lenses with the Seikosha shutter. Its a good shutter but when it goes wrong It will be practically impossible to repair due to lack of spares. Always go for the black lenses.
In order of preference
I would discount the Mamiyaflex C2