The elephant in the room with zoom vs prime is cost. While wide-angle zooms are not cheap, and GOOD wide-angle zooms are very pricey, a 16-35-ish pro-quality zoom is usually not much more than a single fixed prime in that range. I used to have a Sigma 18-35 f3.5 for my Contax SLR outfit, and while it was about $500 new (back in the early 90's), just the 28 f2.8 and 25 f2.8 alone would have set me back closer to $1K. Not to mention any of the really wide lenses in the Contax lineup, like the 21 or the 16.