Pentax 645, Pentax67, Mamiya RB67, Mamiya C220/C330 all are professional and relialable cameras, offered at reasoable price now. Many KIEV60 have problems that are expensive to fix; Lubitel isn't a professional camera. I bought a quite new Mamiya C220 with 80mm lens for 150 euros, so IMHO it's a nonsense to buy a toy-camera or an unreliable KIEV60.
What camera to chose? It depends mainly on what are your preferences or style: indoor/outdoor, tripod/handled ecc.; anyway all professional camera are built to be durable and to meet the requirements of heavy user.