This Sonic Drive In is just outside the strip but despite averaging only three stars on Yelp, I think it is one of the better Sonic Drive-Ins simply because their employees are incredible in terms of service, courtesy, and promptness. I couldn't believe how they bend over backwards to zoom out on roller skates and get you your order quickly or provide you with refills, etc. I mean, granted the food isn't all that great, but their service was way better than what I experienced at L'Atelier de Joel Robuchon!
Tip: 1/2 price shakes after 8pm