I use the Mamiya Universal or the Mamiya Super 23 with an assortment of lenses from 50mm to 250mm. The 6x9 backs I have hold the film flat and produce sharp negatives and transparencies. Some people consider them heavy but I don't find an issue especially if you have been used to using a Linhof 4x5. Cameras and lenses are reasonably priced and available, seals on the film backs are easily replaced and there are no bellows to worry about.