I've looked at the Rattlehawk many times, I think it's gorgeous. The vids of it at work prove that it's no slouch, I've just never bought one.
I have the Shrike, love everything about it. Only thing I'd change would be to add a bit more texture to the handle. It's a beast otherwise and well worth the money.
That answers which one for me but even though I've already made that decision I couldn't tell you why. They both have great resale value so don't worry too much about buyers remorse or wishing later that you'd chose differently, you can always sell and buy the other at a minimal loss.
Get the one that's pulling on your wallet harder and have some fun.
If you get the Shrike remember to take the sharpening stone out of the handle before you bust stuff up or you may crack the stone.