1. It was difficult to miter the facing AFTER it was stitched to the quilt. The quilt's bulkiness made marking a 45 degree angle awkward and inprecise.
2. I didn't like the look resulting from not being able to take the understitching (which keeps the facing from rolling to the front of the quilt) all the way to the corners.
I really like the look of the piece without the distraction of a binding and know I'll use this kind of finish again. But first, I'm going to do a bit of experimenting. Next time I'll either miter the facing before stitching it to the quilt OR use four separate strips of fabric for the facings. Either way, I'll hand-stitch the facing and not fuse it down.