Do most students get along with their randomly assigned roommates?
Actually yes, most students get along well with their randomly assigned roommates, whether or not they become best friends. The roommate survey that the college assigns to its freshmen has an excellent algorithm for finding students that live well together whether or not they become tight friends. It takes into account things such as the times at which students prefer to wake up and go to sleep, as well as how much activity they expect to have in their suites on a given night. In fact, many students choose to stay with their suitemates even in the next academic year, when they can choose whomever they want to live with.
Of course, it is possible that you and your suitemates would not necessarily get along. For example, hygienic practices, which are not specified in the survey, could prove to be a problem between suitemates. This is especially the case for shared spaces, such as the living room and bathrooms. At the same time, the survey does not take into account personal visiting. Some people like to have guests over in their own rooms, which, although not a physical obstruction, can be noisy. Conversations about issues like these are important to have early on in the move-in process to ensure that everyone is on the same page with regard to suite expectations, courtesy, and use of shared spaces.
In general, the trend seems to be that any reorganization of suites occurs after freshman year, for the sophomore year suites. After this shuffle, suite arrangements mostly remain entirely the same for the rest of the college years.