There are large differences between Obama's connection with wright, and Mittens connection with the church of LDS. Unlike Obama mitt was a Missionary for the church of LDS and even lead a mission over in france after he was involved in a car accident that killed the previous leader. Mittens position in the church allowed him to be sent to france so he could avoid serving in the vietnam war. Unlike obama who sat in the pews hearing sermons, mitt actually represented and lead in his church. Much unlike obama who denounced and separated himself from wright after his political messages were revealed, Mitt has never once denounced the church for their activities. To go earlier into mitt's life and family, his family moved to mexico because they were not able to practice the LDS church's pro-polygamy point of view. Mexico allowed them to have multiple wives, and his family was quite fond of the practice and felt it was so important they gave up their US citizenship. You can say what you want about obama eating the local cuisine of indionesia while he was there, but he never had a practice deemed immoral, sexist, and wrong drilled into his head by his family. Of course, mitt has obeyed US law regarding polygamy, and the church of LDS has declared they will live within the laws of the US despite looking to change them to satisfy their religious teachings.
Both of them probably got some help in their early political lives from their churches. However, obama's help ended when he separated from his church and switched to a different one. Mitt still gives to his church regularly, despite any immoral behavior they endorse and act out, and he has never spoken badly about their using tax free money for the sake of campaigning which is against the law.
if you want to get into philisophical differences the church obama attended saw jesus as their saviour. Mitt and his church worship a fasle god and break a commandment by worshiping Smith over jesus. This would mean that mormonism counts as an extension of the christian faith, like islam, but is not christian because of their worship of false prophets. But if you are not part of the christian faith tree this is all pointless as they all worship the wrong gods, or nonexistent wackyisms.
So it is a bit different considering the immersion Mitt has with his religion, and his admitted devotion to it. Obama seems to regard himself as president first and a christian second. he has admitted that his first priority is for the people of the US who do not abide by the christian faith. Romney seems to feel he is a mormon first and a US citizen second. No offense, but I don't want to be forced to abide by mormon law as much as I do not want to be forced to follow christian law, or any other religious law for that matter. We also know from their participation in prop-8 the mormon church thumbs it's nose at the restriction keeping them from campaigning or donating tax free money to campaigns.