I've got the earlier G690BL which I bought with the standard lens, then added the 65mm f8 a little while later. I ended up getting the kit for less than one fixed lens 65mm camera. Thing is, I had the luxury of time....
I didn't get the accessory viewfinder with my 65mm, but using the whole viewfinder approximates the field of view well enough. I also had the option on one of the longer lenses (I can't remember whether it was the 150mm or 180mm), but having shot a couple of nice portraits of my young son with the 100mm lens, I decided I really didn't need it (can't believe I actually said that!).
While I've not fired the interchangeable G alongside a later fixed lens camera, I get the impression than the older camera is quieter. People only seem to notice the size, and the is usually only after a double-take (camera : person proportions look wrong ).
They're easy enough to carry around for several hours at a time. I find it easy to shoot mine hand held, but obviously that is not making the most of the excellent lenses.