I purchased two of these X86-P5 units to use as network routers, installed OpenWrt on them, and they do a great job routing packets at the interfaces' full 2.5 Gbps speeds (when connected to LANs or WANs on both interfaces that actually support these speeds).
The build quality of the units is very solid. They do get a bit warm if left in a fanless configuration, but this doesn't seem to negatively impact their functioning otherwise.