I've had an R1 for about a month, as I also thought this might the one I've been waiting for. I can't answer most of your questions as I don't know Nikon stuff well enought to compare. However, you can download the manual over on the Sony web site. (Not that it will tell you much about what you want to know either) But, it does have a matrix meter, as well as a center weighted meter, to go along with that spot. No multiple exposures on the same 'frame'. (Not sure that question still makes sense in a digital world...) You can however bracket, and then open all three files in PS or whatever, and merge them. I think that's the same thing, if I understand your question. I'm a very amature photographer who shoots maybe a 100 shots a month and prints one or two of those - but I really like this camera, the images, and the lens covers most of what I want. It seems very well made, (it's not a $3000.00 camera nor a Leica M, but it's nice) and I love the way the dials work to change settings, etc. Almost like having f/stop rings and shutter speed dials like my OM1. Anyway, thought I write and say how much I like this camera - try handling one in a shop and see what you think.
Ray H.