Yup, the downstairs and upper back corner are a saving grace for the SFO lounge. Usually they're quiet and empty on the busiest of days. No such luck at EWR.
I usually eat at the Centurion and over to the PL when I want to work. I don't bother with those little conference rooms across from the desk. The sound insulation is horrible and you will likely overhear desk agent conversations that will make you despise UA even more.