Been a Soviet Russia's dweller I have tried once a medium format camera. In 1982, I bought Lubitel 166B. Lubitel is a TLR (twin-lens reflex) 6x6 camera, part of old soviet cohort. It is very cheap (plastic everywhere) but somewhat discent camera. Unfortunately, it drowned next spring in Berezaika river along with some of my 35mm lenses leaving just couple of 120 slide films.
When in USA 20 years later I've got this idea to try medium format again. In 2004 I bought Bronica ETR with 50mm Zenzanon, prizm viefinder, grip handle and 120 back. Then I added some lenses (75mm, 150mm and 200mm). I also tried the motor drive and did not like it (it is too heavy/noisy).
Bronica is a very good camera. It feels a bit flimsy, but actually it is not. Very dependable. The quality of lenses is differ from one model to another; there are very good Zenzanons (for example, my 50mm is an excellent lens) and there are just good (my 150mm). But all of them are definitely usable.
This is shutter-in-the lens 645 (6.0 by 4.5sm) system, so the body itself has very simple design. There are some unusial features compared to 35mm SLR: mirror is up until you cock the shutter (it is true for the first 35mm SLRs, too). Changing lenses could be tricky in the beginning. But otherwise it feels and handles as a big and bulky 35mm SLR. I can definitely recommend this system to a creative photographer; its a shame that Tamron closed Bronica line (Tamron now owns Bronica). Here is your internet resource for medium format cameras in general:

Medium Format Camera Megasite

and Bronica in particular:

Bronica ETR review

Please see some of the examples of my work in MF on this page and in my other galleries.