The Falcon 9 (1.0 and 1.1 combined) has had one partial failure and 12 successful launches, the Antares one complete failure out of five launches, the Delta II one failure (and one partial failure) out of 152, the Delta IV Medium 20 successful launches with no failures, the IV heavy 7 successes and 1 partial failure on a test flight, the Atlas V 51 successes and 1 partial failure. Yes, the Delta III was horrible, but it was only launched three times back in the 90s and abandoned.
The DoD launch you're talking about happened in 2007. No other US company could get a satellite in GSO at the time. SpaceX had only launched two Falcon 1s for DARPA at that point, both too small, and both failures. Orbital at least had their Pegasus... with ~1/10th the required payload and a poor success rate.
I'm not a ULA apologist, they were simply the only game in town for US satellite launches, and charged accordingly. SpaceX's recent successes have put them on track to become serious competition, and that's great. But you'd be crazy to trust a new space company with high-value payloads until they have a few successful launches under their belt.