I am one who uses the Smart Cover without any back protection on my iPads. Never had any problems with the iPad 2, the iPad 3 still looks as good as the day I brought her home, and the new iPad Mini looks terrific, too. I will add, though, that with the iPad Mini, since she is brand-new (just got her this past Tuesday) and since her back is black, while I have the Smart Cover on the front and use her with that around the house, when she's not in my hands, just like the other iPads she is always positioned on a stand rather than lying flat. When going out, I pop her into a RadTech sleeve that I had bought for one of the earlier iPads, and that protects her back from junk in my purse. Because the sleeve is meant for a larger iPad it is really easy to pull the iPad Mini out of it and to pop her back in. This is what works for me.....
Ditto, no back protection & so far so good, but I do worry!