I have used student learning groups for projects in the past. I find that students at first dislike group work because they fear that not all members will do their fair share. I allow the students to pick their own group members, assign a project that easily breaks down into equal parts for the number of students in the group and allow the students to "grade each other" by writing what each member of their group completed for the overall project. I found that once I put these things into place I had far less issues with the learning groups in my classes. Students want to know that everyone gets the grade they deserve and don't want one student doing all the work while the other members get the same grade.