It varies over time. Recently, PSP seems to be among the easier ones to get. In the last class, the most junior guy got PSP and was the ONLY one in the class to get his first choice. 3 years ago, YUM awards would be passed off from class to class with the junior guy getting stuck with it, usually. I've seen people left with SLC some time ago. A couple of classes ago, the MRY slots went to the three junior class members. FAT has also been widely available.