Upload & Sell: Off
I've owned my 1DsIII for about 2 years now, I sold a 5DII to help pay for it and have never regretted the trade, nor does the 5DIII tempt me at all. The only two things I miss from the 5DII are the higher resolution screen and those "C1,C2,C3 knobs" that I found very useful. For a landscape/architectural photographer I think the 1DsIII is a great camera and at the prices I see lately a "best buy" for someone who doesn't need the highest ISO or the fastest fps. Focus is spot on every time, image quality is outstanding, build and water-resistance are outstanding, I put my 24mm TS-EII on it and I'm a happy camper.
With respect to the review time you mention, that depends to some extent on the card I use. The newer "extreme this, ultra that" cards seem to help with the review time, at least to a point that it doesn't bother me. With respect to start-up time, mine seems to start instantaneously. Maybe it's .2 seconds but that's much too fast a speed for me to differentiate from instantaneous.
As for the shutter sound, it is what it is. Like you, I come from a background of large format cameras so everything digital sounds loud and weird compared to a large format shutter. As for medium format, nothing is louder or more disconcerting than the explosion I heard from my Pentax 67 when I tripped the shutter.