Powerline (unless it's gigabit kit) is usually equipped with 10/100 ports, even the 500-600Mbit kits. 100mbit less overheads isn't going to give you much more than 12MB/s. Personally I'd go with a cable if at all possible, if not then gigabit powerline, wifi would be my last resort.
I'm using 1200Mbit Gigabit powerline adapters.
I just did some testing - Used a spare AC750 router as a repeater and connected the server to that via a cable. Kind of emulating the setup if it had it's own wireless network adapter. Got 8-9MB/s across the lan.
I must have shoddy electrics in the house
