I definitely find a huge quality difference between sex with a loved one and from when I used to have sex with people I wasn't emotionally connected to. Part of that may just be natural growth, I was a different person then, but "making love" is a lot more fulfilling and pleasurable than "fucking."
Besides the physical expression of the love we share, it's also just better sex. When you're with someone who cares about you and loves you and cares about whether you're having fun, you're bound to have more fun than with someone with whom you're just masturbating on/into each other.
My husband is really into fisting and that's largely for the power exchange. He loves the "puppeteer" analogy. His emotions with that are vastly different than when we have sex. In fisting other people, he loves the ability to take them to an amazing place, give them an earth-shattering orgasm the likes of which they've never imagined, and leave them puddled in a heap. When we make love, it's much more emotional and considerate. We cuddle after, talk about our feelings (he doesn't really like to talk about his feelings, so that's something I really enjoy), and basically ride the oxytocin wave.
Gralson: my husband (works out of town).
Auto: my girlfriend (lives with her husband Zoffee).
The most dangerous phrase in the English language is "we've always done it this way."