What are the real costs and benefits of the US Senate's Immigration Reform Bill as written?

Here is the actual bill. The nonpartisan Congressional Budget Office (CBO) said that the Senate Bill would cut the federal deficit by $175 billion over first 10 years of its enactment and by $700 billion over the decade after that. The CBO also put out a second economic estimate that incorporates the broader economic impact of reform. That showed even bigger gains. In stark contrast, the right-wing think tank, the Heritage Foundation claimed that the Immigration Bill would add $2 trillion to the federal debt over the same 20 year period. Those two estimates are so wildly far apart one has to wonder which report authors were smoking the wild weed when they wrote their version of what immigration reform would do to the budget.

Former Commerce Secretary Robert Reich has made a short video in which he explains why he thinks the CBO’s version of Immigration Reform is closer to the truth. So may the games begin. Who is telling the truth about Immigration Reform’s cost, and who’d blowing smoke? Why do you think those distorting the picture are doing so?