Well, my response (#23) was intended to be serious, and it sounds quite similar to what at.your.cervix describes, with the exception that in my experience some girls like the sensation, some girls don't, and some girls really don't seem to give a shit.
As for myself, I would describe it as a good sensation, but I suspect that it is more satisfying psychologically than physiologically. There definitely is that instinctive need on the part of most guys to get as deep as possible, probably an evolutionary drive that is hard-wired in our brains. It is a satisfying sensation to feel as if you have really filled a woman up to capacity, but the actual physical sensation of having my glans compressed is OK, but not that great if one thinks about it dispassionately.
Some women will, however, really tighten down around the tip of your cock when you can get into that pocket beyond their cervix, and that generally feels pretty great when it happens. Apart from feeling good physically, it gives you the sensation that her pussy is actually responding to your penis.