Not introduced this year, but I'd add Odroid C2 to your list for consideration.
From my POV, the Top 10 was disappointing and boring. AFAIC, there's no SBC competing with the XU4 in terms of perf/$. I'd hope to see something even better than the XU4 or C2.
I'm particularly interested in the 3 GB RAM but the description is ambiguous, still I'll check it out.
I missed the bottom: Basic @ $90 = 2 GiB, Pro @ $120 = 3 GiB.
That price is high and I was specifically talking about !/$ so this unfortunately doesn't really change the landscape.