When I had sex for the very first time, I was NOT prepared for the intensity of the sensations from a vagina enveloping my erection. It happened with a virgin girl, so it wasn't the result of any special skill she had developed. We had done handjobs, and blowjobs, and dry humping before that, and I had been masturbating since I was about 7 or 8 years old, so I knew what my orgasm was like - but intercourse in her vagina was VERY superior.
. . . orgasms inside a vagina just feel more complete. The stimulation is more all-encompassing, and the build-up prior to the finish is more steady than those occurring via a hand or mouth. For the longest time, it was the only way I’d ever finished.
Yes, more "complete". More satisfying. More fulfilling. And more intimate, as
@Huaimek186 mentioned in his post. As evidence to support this, consider what
@6inchcock mentioned: after an orgasm inside a vagina, it's a longer time before you want to do it again (or, COULD do it even if you wanted it). I can usually produce a sharper, harder, orgasm in other ways - masturbation, or anal sex, for example - but even though they may be stronger in some physiological sense, they are not as satisfying in mental or emotional ways. (Of course, sometimes you are actually looking for that stronger physiological response.)
The intensity of an orgasm inside her vagina may indeed be related to the way her vagina envelopes your whole erection without concentrating the stimulation over a small area.
I would add that all of the above comments apply to a bare penis inside a naturally lubricated vagina. I have almost never used a condom, but they always degraded the stimulation and reduced the satisfaction of the orgasm.