This is a good point that calls for clarification of the OP's subject and composition preference. I saw mention of family travels, but the question is, will he be doing wide landscapes on those travels, portraits, or (for example) bird-watching? The C330 body is large(-ish) and heavy, but its short lenses are small. Once your camera bag has made the up-front investment of space to carry the body, you can chuck in the normal 80mm lens and the wide 55mm (for broad landscapes) in spare corners. (Do not attempt with, say, the original 55mm for a Pentax 6x7!) But if you were going to be chucking in the Mamiya's 180mm and 250mm, it would be a very different question. That's where the fact that each of its lenses is a twin-lens starts to hurt.
Originally Posted by MattKing