Boeing's SLS rocket (which is, at its best, 1/4th the power of SpaceX's ITS) depends on NASA to spend ~$60 billion before it could get half a dozen people to Mars in the late 2030s. Updates to the Delta IV heavy could've gotten there sooner and for ~$10 billion, but Boeing is not able/willing to spend its own money to do it; it wants to use government money to get there, and the government wasn't interested in their existing hardware. It's a shame, really. [0]

From [0]: "Senator Orrin Hatch made sure the new rocket used solid boosters, manufactured in his state. Alabama Senator Richard Shelby insisted that Marshall Space Flight Center design and test the rocket. Florida Senator Bill Nelson brought home billions of dollars to Kennedy Space Center to “modernize” its launch facilities."

Yuck.

ITS, on the other hand, is claimed to cost ~$10 billion, and begin putting people on Mars (in lots larger than half a dozen, mind you) sometime in the 2020s. Yeah, it's ambitious. They've missed other ambitious deadlines.

I personally feel, subjectively of course, that SpaceX is more ambitious and "hungry" to go to Mars than Boeing is. But that's just my gut feeling, and I have no data to back that feeling up.

[0]: http://arstechnica.com/science/2016/09/how-i-learned-to-stop...

Orrin Hatch is still alive and meddling with things? Ugh.