Why is the staff at American Fresh Brewhouse dressed in vests like it’s a Chotchkies? We don’t know, but it kind of sets the whole tone for this place, which is Slumbrew’s more dressed-up, corporate-feeling location in the Truman Show-esque development that is Assembly Row in Somerville. The beer is still good here, but the food is mediocre, and it’s hard to really enjoy hanging out in what is essentially an outdoor mall.