The difference is, R-Studio doesn't attempt to piece back together broken and fragmented mp4 files. CNW (if you're using the correct MP4 recovery mode) can actually try to stitch together working parts of what video remains.
We specialize in data recovery from failed hard drives and RAID arrays among other professional data recovery services. This forum is dedicated to the sharing of information related to the field between other professionals. Our belief is that we are all more successful if we share our knowledge rather than try to keep it all locked up as a secret.