Current popular QOTOM or similar hardware for home UTM-9?


I'd like to change my home UTM-9 hardware from an old PC to one of the newer QOTOM-like devices.

I need four NICs - WAN, LAN, 2 WLANs.

Price is an issue, I'd like to keep the total < CDN$375 (US$300) if possible.

I'd appreciate recommendations and any 'gotchas' I should look out for.