I hand sew mine unless they are for charity. Our local children's hospital asks that everything be machine stitched. I've done it both ways & hand stitching really does give a nice, smooth finish. It doesn't take that much time & I love doing handwork anyways.
I learned from my local AQS appraiser that machine and hand stitching can be equally strong; it just depends on how many stitches per inch & the type and quality of the stitches formed. Go with whichever you prefer unless you are entering it in a show (in which case you'll want to hand stitch it).