In NASA's new budget, the Constellation program has been cut in favor of funding for commercial space companies. While I am sad to see this program go, let's compare the near-term products of Constellation vs. one of the leading private companies, SpaceX.
Constellation's first goal was the construction of the Ares I rocket, which would've carried a capsule spaceship to the ISS. At the time of its cancellation, it was planned to launch in 2014, although the Augustine Commission reported that it would have been unlikely to fly until 2017. It would've had the capacity to carry 25,000 kg to lower-earth orbit.
SpaceX is also in the process of building a rocket to carry a capsule spacecraft to the ISS, which is called the Falcon 9. Unlike the Ares I though, its first rocket is already on the launching pad, with a launch scheduled sometime in the next month or so. While the first launch will only be able to carry a payload of 10,450 kg, a "Heavy" version is planned for launch this fall with a capacity of 29,610 kg. SpaceX's capsule spacecraft, the Dragon is expected to launch this year, and CEO Elon Musk has stated that the last remaining barrier to a manned mission is the development of an emergency escape system.
So, with the Falcon 9, we're looking at a slightly more powerful rocket that will be launched 4-7 years sooner than NASA's version and will carry a similar spacecraft to similar orbits. Keep in mind that SpaceX is only one many private companies with achievable near-term goals. Why exactly should we pump any more money in to the Constellation Program?