I decided to get the Wii version as I found it better than the GC version. The main reason for this is because I have a HDTV and RGB doesn't look nice on a HDTV set. The UK GC doesn't support a Component cable and because of this I decided to get the Wii version. I must have superior picture quality when playing a game which I know will be dam good. Another good thing is the Wii version also supports a 16:9 screen ratio unlike the GC version.
I know I could buy the GC version and play it on my Wii but that seems pointless to me.