With a payload capacity of 63.8 metric tons to low earth orbit, each SpaceX triple-core Falcon Heavy booster can launch twice as much cargo into orbit as can Delta IV Heavy.
And if you think these two facts might appeal to the U.S. Air Force, you're right.
SpaceX's first Falcon Heavy launch was as much a publicity stunt as a technology demonstration, launching Elon Musk's personal Tesla Roadster sports car into a solar orbit past the reach of Mars -- but generating no revenue for SpaceX.
In late June, the U.S. Air Force awarded SpaceX a $130 million order to put "Air Force Space Command-52 satellite [into] its intended orbit.".
Now, aside from SpaceX, the only U.S. launch provider capable of launching payloads this big is ULA.
As for Falcon Heavy, it has only launched once and only been bid against a ULA Delta IV for a USAF contract once, but it's won that one contract, so it's also batting a thousand.
For government launches, SpaceX is charging an average of $96.9 million for Falcon 9 launches, and (so far) $130 million for Falcon Heavy launches. »