I picked up a couple of these and I have to say I'm pretty impressed. They're pretty inexpensive little machines and they ship quick from pcengines.
I have openbsd on one and ubuntu on the other. I'm using the openbsd one for dns, tftp, and a handful of projects. I was thinking about making the ubuntu one into an ap but I'm not sure about what kind of performance to expect vs my current off the shelf router. Have you used it as an access point?
I have an older APU1C4 with two WLAN cards (WLE200NX) and it's hosting two physical APs and a few virtual ones (diff BSSID/subnet one running at 2.4 ghz other at 5). I just run vanilla Debian on it... The SD card has finally become corrupted over the years, however. When I reboot it, all my changes that were supposedly flushed to disk are lost. Thankfully I only reboot it occasionally when there are critical kernel updates. I just rsync over the filesystem in memory to facilitate restoring the previous configurations.
Anyway, I run various services on it, aside from hostapd... It acts as my firewall, gateway, access point, and runs some other services like nginx to proxy some services from my LAN across subnets (like plex, etc) and motiond as a security camera monitor. I've used it as an SSH style VPN at times, in a pinch. When our WAN goes down I can simply plug my phone in to the APU via USB and tweak some iptables rules to use the LTE connection from the phone over USB network interface.
I also have a newer APU2C4, along w/ an AC WLAN card and an msata drive... have had it for years just sitting there, grr. I really only got the newer one since it has AES-NI support on the processor and I can do much heavier VPN traffic, but the SD card issues have become annoying, so I think this post has encouraged me to finally set it up this weekend... Thanks :P
Anyway, I wouldn't hesitate to pull the trigger on any of the pcengines stuff... Go for it!
Just make sure the WLAN cards you use are well supported via hostapd. :)
I installed OpenBSD on my apu and picked up a Ubiquiti AP AC Pro for wifi. I also picked up a couple wifi nics that I'd intended to use with hostapd as you suggested. However, I had some spare amazon pts to throw at the Ubitquiti hardware, so I figured I'd give it a shot. It was all super simple to set up, and I'm more than happy with it so far.
Previously I was using an ASUS RT-N66U with tomato/shibby, but it had been acting a little flaky for a while - 5ghz would stop a few times a week, eth connections would drop, overall wifi connectivity was mediocre at best. The performance was pretty similar before flashing with tomato.
My new solution is likely drawing a little more power, but I've had no problems with it. Also, I'm impressed with OpenBSD's simplicity. I've tinkered with FreeBSD in the past and found it a little complex. OpenBSD has proven to be significantly more straightforward and easy to configure.
I have openbsd on one and ubuntu on the other. I'm using the openbsd one for dns, tftp, and a handful of projects. I was thinking about making the ubuntu one into an ap but I'm not sure about what kind of performance to expect vs my current off the shelf router. Have you used it as an access point?