While I love the files from my Aptus 54s, they aren't much different from the 5d2/1ds3 files. I think the real difference is in the way the lenses render. I'd stick with the Canons if you can't have both.
All I know is if I had never bought anything but a Canon, just stayed on that path and devoted my disposable income and time in another arena I could have owned a RED with a complete Zeiss Compact Prime lens package.
Now at the time I bought my first digital back there wasn't a RED, there wasn't Zeiss mini primes, but when you step back and think about for the price of medium format buy in and learning curve you could buy a 4k motion camera, lenses and build a reel, the difference in where that puts your career vs. shooting only stills is for me a big difference.
Now today would I buy a RED, dunno because I have that weird lingering fear that the RED will become the motion camera version of a medium format camera.
I hope not, but we'll see.
But right now owning two phase backs, 4 contax cameras, three Nikons, Three Canons, one Leica, One Pansonic and three Canon Video cameras my workflow is 90% Canon (stills and motion), 5% Nikon, 3% medium format, 2% Leica.
But just to add if you really have a hankering to buy a big megapixel camera look at the world of used. The difference between a H mount P40 and a used P30 is a lot of money.
BC