I would have chosen the i3-n305 version of that motherboard because it has In-Band ECC (IBECC) support - great for ZFS. IBECC is very underrated feature that doesn't get talked about enough. It may be available for the N150/N355, but I have never seen a confirmation.
what is the impact on performance, does it require special ram? just heard about this here
Can you explain why ECC is great for ZFS in particular as opposed to any other filesystem? And if the data leaves the NAS to be modified by a regular desktop computer then you lose the ECC assurance anyway, don't you?