I eat at Great Wall on a regular basis. The owner is always friendly and the staff makes sure you're taken care of when you dine in.
We usually order take out, which is always ready if you all ahead. Dining in can be hard on a busy night - there usually aren't a lot of open tables.
The food is terrific. I usually order orange chicken. The beef and broccoli and the Kung Pao shrimp and chicken is delicious.
If you're in the east Valley, it's definitely worth the trip.