* Most of my client devices are from Apple, and I easily got the best WiFi performance overall with 802.11ac-capable Airport Extremes, which is impressive given how relatively cheap they are. However, I'd like multiple SSIDs, and Apple gear can't do that (the guest network support doesn't count). Regardless, Apple is out of the game, so this isn't a long-term solution.
* The UniFi gear had terrible 802.11ac performance, even when my devices were in the same room as the WAP. At the time, I was using first-gen 802.11ac hardware from UniFi, so it's somewhat understandable, but the poor performance combined with 2 of the units failing within the first 6 months didn't leave a good impression.
* The Aruba Instant WAPs were reliable and got good performance (though not as good as the Apple WAPs), but I'm not a fan of their licensing. Without a support contract, it was possible to hunt down the latest firmware updates, but they didn't make it easy.
I recently bought a PC Engines APU3C4 with a mini-PCIe WiFi card and a couple of Chaohang antennas [1], and I'm contemplating build my own WAP. This would give me all of the configurability and tweaking that I want, and I could deploy it as just another piece of my personal little devops pipeline.
However, I don't know much about the RF side of things. I'm aware there's a lot of black magic involved, but it's not clear to me how much performance and/or range I'm going to lose by piecing together COTS stuff versus a professionally-engineered solution from Ubiquiti et al. If anyone who's reading has built their own WAPs, I'd love to hear from you.