I must say: the ERL is terrible hardware.
You can get some performance out of it if you're using Ubiquiti's kernel, because it ships with a series of highly specialized proprietary modules that offload packet handling to hardware accelerated modules, for their custom proprietary network stack. But their kernel is old and shitty, and if you want to do anything interesting with the ERL, you have to build your own kernel.
So for any mildly interesting usage, it fails considerably hard.
And even if you do opt to use their closed-source binary blob kernel modules and software stack, as soon as you try to do any sort of advanced networking, you run up against the limits of their acceleration modules, and the OS is forced to fall back to standard non-accelerated mode, and performance drops. Try using PPP, any interesting iptables, MPTCP, OpenVPN, interesting routing tables, or anything cool: performance drops.
I would be very happy to see some small networking hardware with multiple independent Ethernet controllers pop up on the market for a decent price; every other month or so my disappointment with the ERL moves me to re-research this. Unfortunately, the EdgeRouter Lite is not the hardware anybody wants for interesting low-cost networking.