I quilt first..ALWAYS. You will like your finished quilt better. After that its a personal preference. If I quilt it on the long arm, I often apply the binding on the top, then unload, then trim, then do the hand stitching on the back. I try to square up the corners as I go along, marking the squared edge if necessary as a guide. If I apply the binding on the quilt on my DSM, I trim first, then apply, then turn. I really rather do it on the long arm, but sometimes its just not feasible. (like on my show wallhanging I just finished...it was a 10 sided quilt. I decided to do the binding off the frame!)