The Hilton Garden Inn Addison is a nice place to stay. The place is very clean and the service is very friendly. But if you stay in room 227 and sleep in the bed on the left, watch out for the big dip in the upper half of the mattress. Laying on my back with all of the pillows was sort of OK. But trying to sleep on my stomach, I felt like I was hanging off of a cliff. After switching to a more diagonal position, it felt a little better. The mattress needs to be flipped, rotated and/or REPLACED.
Also, the not included breakfast seemed a little expensive for what you are getting. At $14, the food seemed close to standard "included hotel fare". Go to IHOP a mile down the road for more choices at a lower cost.