Which version of Android used makes a difference. Plus some have bugs - like the Galaxy S (1) and it crap filesystem it used.
I have a couple of said junipers and a dual core 1ghz android. The juniper is fine in production for hundreds of mbits and many users (even the bittorrenting ones) if you disable all the connection tracking and firewalling. The smartphone on the other hand is the biggest price of shit ever shipped. YMMV.