For series that don't have reviews or recommendations posted, the next place I look is blogs, just to see if anyone has mentioned the anime. Sometimes, I find a person giving reasons why they dropped it or just giving a basic plot overview, so they definitely can be useful.
this is also why i think having better visibility into forum threads would be very helpful - as the currently airing series threads are filled with stuff lke that, and older titles might get discussions going too, if there was a better setup for them