I want to know if now it's a good period to buy AmigaOne.
The decision is absolutely emotional. No one wants an a Linux box so expensive and troublesome. (With troublesome I mean it's PowerPC, which has worse support than X86 Linux) Still no one knows how good/bad OS4 will be.
So those who already bought an AmigaONE did that purely based on emotions - yet, I don't want to underestimate the power of emotions. They keep our life in movement.
So put your hand on your heart and say out loud: do you want it or not?
If it is what you've dreamed of, and have the money I say, go for it. If you want to be rational, then the answer is "not" or "not now", and buy something else or wait how this will turn out in the end.
Whatever your decision will be: You will not be disappointed. It's almost impossibble psychology wise. :-)