I think the point here is, buy a Cold Fire if you have apps on your Amiga now, which need more power... ray tracing, music processing and image processing springs to mind.
I love the idea of the cold fire, it's about a community taking the bull by the horns and seeing just how far they can go... do you see Atari or MAc users trying to get that little bit extra out of hardware that is over 10 years old... no, Why, becuase their hardwear was nothing special, it was "standard for the time", not excpetional it did not make people think "I'll bet this thing will go faster if I..."
Just my $10,000,000 worth :-D