I've been there on four occasions. I believe that in order to try a place, you should visit it various times, because sometimes due to circumstances, you may not leave with the appropriate impression.
Every time I've been there, the Salvadorian Pupusas were practically swimming in lard or grease.....NOT what a pupusa should be. They are carefully shaped and flattened into their distinctive shapes, while not allowing the food to fall out. Then they should be cooked gently not burnt, fried, or battered with grease so they cook quickly. They cheese should never be monterey jack, that is just wrong and inadequate for them.....tooo much grease. All four times, my pupusas were dark, or burnt and what really upset me was that the lady didn't have an idea as to what lorocco truelly was! WTF....that's the whole point of the pupusa!
If you want to eat mexican food, you to to a mexican restuarant, chenese, you go to a chinese person who actually appreciates the culture and delicacy of their nation's values in food. This is just wrong and rude.
If you want to try authentic pupusas, in a much more sanitary way and healthier choice I recommend going to the Fair oaks soccer fields on Saturdays and Sundays. There's a lady who works in a mobile-food-stand-truck who is from el salvador and hand makes everything from the flower, beens, chicharron (fried pork bits), and actually uses salvadorian cheeses. She does not apply grease to the skillet. While it does take a little more while, you do receive something worth wild and your time. The school is in redwood city, off the Woodside Road heading Eastbound right before Smart and Final.
Amelia's is not authentic salvadorian food.....you have better luck off this little truck-stand than in an actual restaurant.
Good luck and Bon Appetite!