I presume your test with LEDE r4018 is using my firmware build?
Yes, they are amazing. I went a head and tested all of them and all the other versions I could get my hands on from LEDE through to OpenWrt.
Your r4017 version is so far the best in terms of WiFi. It reaches stock performance with around 102 MB/s with my 3x3 adapter and without tweaks.
Stock Lede 17.01.2 and 17.01.5, reach 90 MB/s with performance governor. I'm happy to share all my results if someone is interested. OpenrWrt 18.0.1 won't go above 50 MB/s, no matter how much I tweak.
Stock various 100 MB/s (crashes)
To be exact, connections fail with a decryption error. This is very visible with large file transfers, which makes the AP useless. I've reproduced the behavior on two different R7800s. I've also tested various stock versions and with Voxel's modified stock.