I have a Flexaret IIIa, which is a nice enough camera, but I haven't used it much. Mine has a triplet, but you'd probably want one with a Tessar-type lens for better overall resolution. In TLRs, I've also got a Mamiyaflex Automat A with Olympus lenses, which is very nice but overly complex and rare; an Old Standard Rolleiflex with an uncoated Zeiss Tessar, which I love dearly but is not the most ergonomic camera (a later Rolleiflex or Rolleicord would be a better choice for a first TLR, I think); and finally a Zeiss Ikoflex Ic, which is much more modern in design and execution, and has a later coated Tessar - this is a very underrated and capable camera with an excellent lens, a bright viewfinder, and a built-in meter.
If you can find a good later Ikoflex with a Tessar, it will likely be cheaper than the functionally-equivalent Rollei. The Autocords have a great reputation, but I haven't used one (the Flexaret is similar in operation, however). The Ricohflex you mention is likely a relatively generic Japanese TLR, similar to many other -flex labelled cameras of that era - probably OK, but not likely to be anything special.
There are only a few functional differences in TLRs: lenses, obviously, but also lever vs. knob advance, automatic frame spacing vs. red window, lever vs. knob focus, which side the controls are on, meter vs. no meter. Sizes vary somewhat, but most are pretty close (big Mamiyas excepted). If you can, try to handle a few and see what works best for you.