I'm getting more serious about making the necessary investment in having professional quality medium format gear to work with. I'd like to invest in a medium format SLR system. The local camera shop has a Bronica ETR-Si with 75mm lens, waist level finder, and 120 film back for a very affordable price. It's tempting. But with another couple of weeks of saving I think I could get into an RB67 kit. Is there a big difference between the two? Is the Mamiya worth the extra money? I expect this camera will be used primarily for fine art nudes, portraiture, and candid public/street photography.