For me, neither one really helps on the back (one of those had to do it once to say I've tried it kinda things).  But sometimes I do get the scraping when I get a foot massage.  The softer bottoms of my feet promote more foot massages from the gf.

Neither! Both are agonizingly painful! Go for full body massage or oil. Those are relaxing and involve no pain.

I don't think that cupping and scraping can be considered massages. They are important componants of the Traditional Chinese Medicine, as much as massage, but are not massage themselves. 
Now as for your question, i've tried both and although scraping is terribly, incredibly and unbearably painful, it does make you feel a lot better, especially if you have a cold or the flu. But cupping is not painful and does have great results as well. 
I'd suggest the latter...

If by benefits you mean pain, then yes, both are quite beneficial. It's totally worth your money, works like a charm. However, I'd prefer a massage or even just a hot tub, those are much more relaxing.