This link http://www.camerahobby.com/Review-SQAi.html should be a good starter for you.
I used Bronica SQ system for 5 years. The only caveats I'd think of were two: electronic shutter - means you were left with 1/500s. when the batteries went dead and the other - the weight of the system of body + 3 lenses - too much for wandering about in towns or hiking/biking. Now I'm left with my precious and fully CLA'd Rolleiflex 2.8d + Rolleinars and that's plenty.