I would make a recommendation, but it doesn't do any good.
Just think about this, you can buy an 800mhz/G4 linux box for $800US motherboard only...or a faster linux box (pc) for $199 from wal-mart, that includes everything except the monitor and runs more linux programs.
Neither run OS 4 today, one will run OS 4 someday, but not the cheap PC.
However, after spending only $199 on a computer, you can run linux all year, and buy an AmigaONE when OS 4 comes out.
Hopefully by then the price on an AmigaONE will have dropped in half. If the price doesn't at least drop in half, there is no future to that platform anyway. In my opinion, after selling to the fan base, the market will simply dry up.
If on the other hand, it does drop to volume pricing, OS 4 will flourish, but you can always buy it when the price is reasonable.
The reason this advice will be ignored by some is because they want to have an AmigaONE now, even if it doesn't run OS 4, even if only to say they were an early adopter.
Well its their hobby, if they need that, obviously they should go for it.