I will wait for the Natami project to end up hopefully with success... I don't trust on systems that rely on emulation to handle classic software... I can do that using WinUAE.
So under my point of view nor Efika neither SAM are amigas anymore, specially since OS4 is capable of "almost" boot on a Mac... Or finally efectivelly boot.
It's like the new intel Mac's and the Leopard... Leopard can boot on a PC with some hacking. So these machines are not Mac anymore.
And yep, they have some new and nice pieces of software, but i would not spend so much money on a SAM440 when you can get a PC much more powerful for the same price, and use WinUAE faster than the Amiga emulation is on the SAM440...
In any case, i would go for an Efika, it's a fraction of SAM's price, and specs are not far behind the Acube board at the end.
Cheers.