First off, there are two factors that affect how good, bad or mediocre I am at sex: (1) I'm very good-looking, well-built and athletic, and been told I'm sexy as hell ("a hunk"); on the other hand (2), I'm hung like a chipmunk.
Because of (1) I've never had any trouble attracting women (or men for that matter); but (2) makes me a total dud sexually for a fair number of women right off the bat. Even with women I've had great sex with, I'm often too small for them. I never got my first wife off through penetration alone; she enjoyed it, but could never climax that way, no matter how hard we tried. When she was ready, I'd switch to oral (or manual). She could easily cum with better hung men, though (she had an affair with a buddy of mine while I was overseas in the Navy; no trouble at all). Sex with the girl I lived with for two years was great but almost exclusively oral. My current wife and I have great, mind-blowing sex, and I can get her off by fucking, but It's noticeable that she gets off quicker and more explosively with the 7.5 inch dildo.
So, it's a mixed bag. I'm creative, attentive, can get it up and last forever, can bring women to screaming climaxes, but I'll have to admit that, strictly in terms of fucking, I'm not that great a lay - ranging anywhere from mediocre to okay at best. On the other hand, lots of women seem to flip over me, come back for more again and again, and even claim sex with me was some of the best they've ever had. My first wife and the girl I lived with fall into that category.
It's mystifying. I guess what makes sex great differs from woman to woman.