Best Augmentation

What is everyone's thoughts on which GPS augmentation system is the best?

Nationwide Differential GPS System (NDGPS)


Wide Area Augmentation System (WAAS)


Continuously Operating Reference Stations (CORS)


Global Differential GPS (GDGPS)


International GNSS Service (IGS)



Personally I'm leaning towards the WAAS augmentation since it's the one preferred by the FAA although I've seen some good arguments for using GDGPS.


http://www.gps.gov/systems/augmentations/