Comparing today’s two most widely used approaches in software development from Microsoft’s and IBM’s point of view.
General conclusion of the comparisons could be summarized as:
RUP is (1) a formal, strict and heavy software engineering process that wants to (2) identify the requirements and architecture early in the process to be able to (3) focus on planning the time schedules and budget to create (4) a predictive and ordered software development environment.
MSF4ASD is (1) an informal, loosely, and light software engineering process that (2) embraces ad hoc requirements management and architecture design to (3) facilitate the ability to cope with changes to create (4) an adaptive and responsive environment.
MSF Documentation: RUP vs. MSF - A comparative study (link)
Comparing the Rational Unified Process (RUP) and Microsoft Solutions Framework (MSF) (link)