Roger Cole
Member
Weight? Ok, the RB is heavier but is it heavier than your 4x5 kit plus holders, etc you need to carry? Probably not. Also, I regularly carry a RB67 handhled around for shooting so don't know why people say it is a studio camera. You can even handhold it down to 1/15 with a 90mm lens, which sounds silly but it can actually be done. It is just different cameras and I can see myself owning both of these as they don't really replace each other.
My main concern would be the aspect ratio. For me the RB is a vertical camera, ie I shoot it in portrait orientation most of the time. It just works for me, I find the rectangular yet nearly square ratio for horizontal to not work as well compared to a 35mm camera. So think of that first and see how it compares to your 4x5 and final prints/images.
The RB is almost certainly way heavier, assuming a 4x5 flat bed. They're monsters compared to a flatbed 4x5 which can be quite small and compact. Really.
Not dissing the RB at all, in fact I've often been tempted to get one and sidestep the hassles of sheet film, but one reason not to is that my 4x5 kit even with darkcloth etc. can be a lot lighter than any comparable RB kit.