I've used the decorative stitches on my Bernina successfully, but in an unconventional way so I don't know that it would be appropriate for contests unless you are entering the art quilt category.
I attach my binding to the back of the quilt, then fold it over to the front, with mitered corners. I pin or fuse it in place so that is just touches the line of stitching created when it was attached. That line becomes the sewing guide for sewing down the binding on the top - when you start right on top of it, your new machine stitching is right in line with the back edge of the binding.
It is almost impossible to get the stitch motif to end in exactly the same place and things go off track if you start at the top of each side and sew down, so I start in the middle of each side. I sew forward for the lower half and stop at the corner. Then I go back to the middle, insert the needle right in the first stitch of what I just sewed, and sew the motif in reverse to do the top half. Once all four sides are completed, I enlarge the decorative stitch slightly and sew 1 pattern on the diagonal in the corner of the binding to close the miter. I found this technique works best with open stitches such as the feather motif, vines, hearts, etc. Any design where the machine has to fill in sections of the stitch seems to just be too much bulk and makes the binding wrinkley.
Let us know what you decide to do and if you have any luck in the contests!