Neither one is very accurate for advanced cancellations--especially as DL may not have completely worked out their schedule for tomorrow yet. Neither site is updated minute-by-minute either in regard to cancellations and delays. Flightaware is great for real time tracking. Flightstats gives less updates when the flight is in the air. Flightstats tends to be a bit more reliable in calculating cancellations and delays but that data may only be updated once an hour.

Plus you don't really care about every flight. You only care about the 2 you are on Delta could run every flight on time and cancel 1 of the 2 you are taking and your plans would be messed up.