hmmmm...
tried to answer -- but something fouled up
perhaps this is a repeat?

any way
have you looked at chowhound?
it's a site of food affection -- much talk about anything food.
anyway i found this bit along with lots of other mexican reviews from average joe eating people...

"Extramsg has done a whole boatload of reviews of Portland Mexican restaurants, which I think you can find here: http://www.extramsg.com/modules.php?n...
The bulk of good Mexican restaurants are in Hillsboro, west of Beaverton, or in the north and east sides of Portland. I would check out La Bonita in northeast Portland, but there's a lot of other possibilities."
happy good foodfinding!
m