IMO, the parties will reach a framework agreement on March 31 or perhaps a few days later. All the sides have too much vested to allow the process to collapse right now. Therefore, some fundamental differences will be papered over using general and/or flexible language that is open to each side's interpretation.
As a result, the framework deal will likely be a weak one (and far short of the requirements set forth in UNSC Res. 1696). There will be no commitment that Iran would ship its enriched uranium stockpile to Russia. Iran would also likely be permitted to keep a share of its more modern centrifuges and maintain some of its atomic R&D activities. While general language about verification and inspections--and even stronger rhetoric in the news conference--will be present, concrete details will be lacking. At the same time, there will likely be a commitment to lift most of the international sanctions once Iran reaches a final agreement based on the framework deal in June. To deal with some of the P5+1's views, the lifting of some modest sanctions would likely be tied to Iran's short-term performance and/or a timeframe of a few years. There could be general language that broken Iranian commitments could result in consideration of renewed sanctions, but consideration isn't the same thing as automatic renewal of sanctions.
Finally, one can't rule out the possibility that some additional sanctions relief could be provided for Iran's reaching a framework agreement.
Of course, I could be wrong. But that's how I see things right now.