The subscription only journal Science has a long article on the decision process between the Euopa-Jupiter and Titan-Saturn missions. A few tidbits follow:
"Ronald Greeley of Arizona State University, Tempe, NASA co-chair of the joint science definition team, declared that "the Europa Jupiter System Mission is essentially ready to go. Of course, the key driver is exobiology." And the theme of the proposed joint mission to the Jupiter system is the emergence of possibly habitable worlds."
"The Titan team's pitch is broader. "There's something on Titan for virtually all aspects of planetary science," was how Jonathan Lunine of the University of Arizona, Tucson, NASA co-chair of the Titan Saturn System Mission (TSSM) science team, described it. The mission would investigate how Titan functions as a system, determine how far prebiotic chemistry has developed, and continue exploring Enceladus with a series of flybys."
"By the end of January, they will jointly select one mission to proceed. They [NASA and ESA] are likely to be balancing the technological ambition of the Titan balloon and the 9-year travel time to Saturn against a science focus on Europa. After that, though, both NASA and ESA have years of maneuvering for funds ahead. NASA will need to navigate around the fallout from MSL; ESA will have to compete its outer planets mission against two astrophysics projects, and both must overcome budgetary woes from the financial crisis. As Green said, an outer planets flagship mission "is not a done deal.""