I think it's been covered by the people above, but I'll add my two cents worth:
I've got a Koni (100), two lenses (58mm and 90mm), and both the Auto-Ups (close-up adapters) described above. It is a heavy beast, but not impossible to lug around provided you use a wider neck strap. I recently took it (and a QL17) out to San Francisco and traveled down highway 1 with it. I used the Canon for street shooting and the Koni for landscapes and other work. It was hooked to a tripod as I walked through Muir Woods, so I wouldn't think of it as a street shooting camera (though I've tried some of that, too). It's big and bulky, but the glass is extremely sharp and the film back is designed to keep the film very flat. Once I figure out a way to scan my mf negs affordably, I hope to post some of the images I've made with the Koni (in CA and elsewhere)
As for the system, the camera is built like a tank (I've read it was designed for the military) and has a lot of quirks in the safety catches (and that ratcheting film advance deafens the rather quiet shutter). Still, the negatives look great (I use a Hasselblad slr, too, and I think Koni is a lot more bang for the buck), and I'm currently hunting for the fabled 135mm hexanon - check some of the sites above for info this holy grail of Konica glass.
If your camera or back needs work I recommend Greg Weber:
www.webercamera.com
He's fast, affordable, and really helpful (he often gives a lot of advice and has been known to walk people through repairs they might be willing and able to do themselves - I'm all thumbs, so I'll send my stuff to him).
I saved a long time to buy my used Hasselblad; had I known about the quality and affordability of the Koni (Rapid) Omega lenses, I'd probably reconsider my initial purchase of a medium format system. Now having both, I see the advantages of each and I really do like my Koni (it gets some great stares out on the street and old wedding photographer and press guys often start a conversation). Still, I got a barely used 100, 90mm, and back (former property of a high ranking MA Police official) for $350 (my inital Hasselblad set up - 500cm, 80 cf, and a-12 - was $1000 more).
Buy an Op-Tech or similar neck strap, and have some fun with 6x7.