Hello, I recently traveled Sun Country IAD Terminal and had a very smooth trip. Check-in was easy and the employees were polite. The terminal was tidy and wasn't overly busy. Security wasn't lengthy, which is always a blessing. Boarding was punctual and well-coordinated. The gate area offered simple seating and power outlets, but not a lot for food. If you’re flying Sun Country from Dulles, I’d recommend grabbing a bite before heading to the gate. Overall, a decent low-cost experience for the price.