I think females have a similar "pulsing" during orgasm, too, but minus the ejaculation.
Yes, and because none of us have been genuinely male and female at different times no-one can know for sure how similar the feeling is but based on description, and given that so many of the reproductive organs have homologues - organs that started out the same but then differentiated, it is probably a good guess that there is a core feeling which is common to both sexes.
I believe it is the orgasm that is responsible for most of the pleasure and the biggest difference in pleasure is how much tension you have built up to be released during that orgasm. It's like pulling back a bow or a catapult - the further you pull it back the more energy is released when you let it go. Personally, it seems like there is a slow build-up in arousal that starts at the end of the previous orgasm and requires no external trigger, i.e. the longer it has been the hornier I am. Add to that exposure to sexual stimuli and then finally there is deliberately edging - getting close to cumming but then not quite going over the edge and building up a bit more. So, the more I have built up to the orgasm, the more intense it is and there can be quite a difference between a really intense orgasm and a not so intense one.
It also happens that my most intense orgasms tend to be accompanied with a bigger, more forceful ejaculation. While I do believe that the feeling of the cum moving along the urethrea is a part of the pleasure, I think it is a relatively small part compared to the orgasm feeling so it more a case that the ejaculation is spectacular because I had a great orgasm than that the orgasm was great because it was accompanied by a spectacular ejaculation.
As for the sensation of peeing, people have already mentioned the relief if you were holding it and really needed to go, but even without that urgency just the sensation of it flowing along my urethra is a slightly pleasant one. Not pleasurable enough, though, that I would seek it out deliberately. I would not, for example, sit drinking water in order to need to go more often, but when I do need to go I enjoy the sensation rather than worry about the fact I was interrupted in whatever else I was doing.