Nanscan, I have not combined the quilting processes but I have blended hand and machine piecing and then hand quilted one quilt. It looked good and kept me on track to finish the quilt in time for a wedding gift. With that said, it is obvious I am not a purist. I think much would depend on the quilt and the quilting pattern that is being used.
I can see one advantage to blending hand and machine quilting being learning a new skill or developing hand quilting while not committing to hand quilting a whole quilt. Good question. I will keep watching for what others think.