On their faces, the two plans contain similar principles for comprehensive reform, grouped into four key areas. Both call for border enforcement. Both call for a path to citizenship for the nation's estimated 11 million undocumented immigrants. Both also call for cracking down on illegal hiring, and for streamlining the processes by which immigrants and workers arrive legally in the United States.
The differences are in the details. One key difference is that while both plans call for more border security, the Senate plan makes a path to citizenship for the undocumented "contingent upon securing our borders" - a difficult goal to achieve - and also upon cracking down on visas overstays. From the Senate plan:
We will demonstrate our commitment to securing our borders and combating visa overstays by requiring our proposed enforcement measures be complete before any immigrant on probationary status can earn a green card.
Obama's plan does not contain such a contingency.
Just in terms of the legalization aspect, both plans call for undocumented immigrants in the U.S. to pay taxes and penalties, undergo background checks and to go "to the back of the line" before they become eligible to earn permanent legal status and, eventually, citizenship.
In both plans, individuals who meet these requirements would initially be able to earn provisional or probationary legal status. But, in the Senate plan, they would have to remain on probationary status until the nation satisfies the enforcement requirement.
Another key difference is that Obama's proposal specifically addresses same-sex couples:
It also treats same-sex families as families by giving U.S. citizens and lawful permanent residents the ability to seek a visa on the basis of a permanent relationship with a same-sex partner.
The Senate plan mentions no such provision.
Both plans address young people who arrived in the United States as minors, and both propose allowing them a way to earned citizenship. From Obama's plan:
By going to college or serving honorably in the Armed Forces for at least two years, these children should be given an expedited opportunity to earn their citizenship. The President’s proposal brings these undocumented immigrants out of the shadows.
And from the Senate plan:
...individuals who entered the United States as minor children did not knowingly choose to violate any immigration laws. Consequently, under our proposal these individuals will not face the same requirements as other individuals in order to earn a path to citizenship.
The Senate plan also suggests an alternate path to citizenship for agricultural workers.
There are other differences in the details, none of which are set in stone as the process of negotiating a viable immigration reform strategy begins. Read the Obama plan here and the Senate plan here.