Really? I have a pfsense firewall and it struggles with gigabit over just one route (80% efficacy), I cant imagine it faring better if it had 5 or 8 gigabit streams at once like the ER-X or ER-lite.
I've always run mine on multi-core x64 SoCs and performance has been as expected. I won't touch their ARM offerings because everything I've seen has been woefully underpowered.