Obama has actually threatened to veto the budget if it includes this funding which puts him at odds with most of the Democrats and many Republicans in Congress. The major reasons for keeping the production line hot are to meet requirements. Another is that cutting the production will have a serious effect on the economy. This during a major down turn will only exacerbate the problems. The defense budget really shouldn't be used as a jobs or stimulus program but in this stressful time the argument has resonated with Congressmen and Senators.
The final bill is moving fairly quickly and the fact that both Houses added the money indicates that it will be contained in the final budget. This will make it difficult to veto as there will also probably be enough votes to over turn that. Obama really will have a hard time considering a veto as the budget will contain most of what he wants. The missile defense budget has not been restored and other then the additional C-17 aircraft in the recent supplemental all of the major programs ended by the the new administration have remained out of the bill. It is a ninety percent solution.
The main argument for ending the production is that the advanced fighter is not needed in the current war on terror. The mission of air dominance that it was built for is not one that is being exercised very often. The price is also very high and the money could be used for more conventional weapon systems. The budgetary pressure faced by the Department of Defense is not so much on buying weapons but paying for current operations. Savings from the F-22 will most likely go to the F-35 accelerated production rather then keeping troops in the field. It would be a hard sell to Congress not to use the funds for other procurement programs just from the economic impact alone.