Well, for what it is worth, there is only one lover I have had who would not let me go down on her. She virtually always had orgasms with vaginal sex in the absence of direct clitoral stimulation, usually had several, and was willing to keep going as long as I lasted.
My wife loves oral sex and virtually always orgasms from it. She loves vaginal sex as well, but doesn't care for clitoral stimulation with it. She occasionally orgasms with vaginal sex, but not if she has first had an orgasm with oral clitoral stimulation.
It seems once she has a clitoral orgasm, she is too sensitive or exhausted to have another orgasm. Sometimes she stops me when she has come close to orgasm with cunnilingus so that she is more likely to have a vaginal orgasm with vaginal sex.
I have had a couple of other lovers who could generally always orgasm with vaginal sex (without clitoral stimulation) or come with oral sex, and they seemed to prefer vaginal intercourse to oral sex (but would agree to either).
I have gotten the impression that for some women, clitoral orgasms seem more like male orgasms, very intense, with a rapid let down followed by a refractory period, whereas vaginal orgasms (in the same women) seem to have a slower build-up, a less frenetic peak, but sort of come in ever more intense peaks like waves on the beach.
But that is just my observation, and I'm sure it is different for different women.