What were the major differences between northern presidential and congressional plans for reconstruction and which was more important.

To answer
the last part of your question, I think it must be said that Congressional, or Radical , was
most important.  First, it was the plan that went into effect and was how the southern states
were readmitted into the Union.  Second, it must be considered most important because the
Radical Republican plan contained the passage of the 13th, 14th, and 15th Amendments to the
Constitution.  The 13th Amendment abolished slavery in the U.S.  The 14th Amendment did many
things.  It said that anyone born in the U.S. is a citizen of the U.S.  This made all former
slaves citizens.  Next it said that no state
could deprive any person of life, liberty or property due process of
law. It also said that no state shall deprive
any person the equal protection of the law.  The 15th Amendment stated that no person could be
denied the right to vote on account of race.  This allowed African Americans the right to vote. 
The passage of these three amendments makes the Congressional Plan for reconstruction the most
important.