I have to disagree that cake flour makes a "better" cake. I absolutely hate the artificial chemical taste that cake flour imparts into a beautiful scratch cake and you might as well just open up a box mix. This is just my opinion of course, so don't blow a gasket on me now
I have found that a combination of unbleached a/p flour and pre-sifted self-rising flour make the best cakes for me. I sift and resift them together and be extra careful not to overmix or overbake. I also use potato starch to help the texture of the cake and soften up the crumb. This way, I don't have to use bleached chemical flours and I can stay true to my "all-natural scratch cake" philosophy
The comments I get on my cakes are that the taste is out of this world but that the soft and fluffy, velvety, buttery crumb is what makes them spectacular.
I read somewhere about using potato starch to help with moistness in a cake. Is this true? And how much do you use per cup of flour?