The Arria 10 (previous high-end Altera series) was at 20nm. The new Stratix 10 is at 14nm. UltraScale+ is in the 14-20nm range, I think, and Xilinx got there first.
(I don't know if you can publicly get Stratix 10 devkits yet, but you can get an Arria at least.)
(I don't know if you can publicly get Stratix 10 devkits yet, but you can get an Arria at least.)