Ok, so I'm rocking on my RB67 these days. Really loving being back in film and loving the 120 format. But...the thing is such a brick its no good for carrying around/casual shooting/informal family shots. Makes me think I might want to add something else that is more suitable. So, whatcha recommend? I like the mojo of the TLR. I'm curious though, the Rollei cameras are going for a hefty premium to the others. Is there a functional reason for that, or is that just "collector value"?