The short answer is: Yes and no.
No it is not "different" from the standpoint of "Is it something that I cannot recognize as orgasm?" It is different in a couple of different ways. After having SRS, you no longer have testicles and all of the plumbing that goes along with that. As a result your ejaculatory response is physically gone. The feeling of orgasm is more of an all over tingle, than a response that is centered in the groin. Multiple orgasms are possible, but that varies from person to person.
And,another, of course, is having a vagina. There is the (in)-famous G-spot, that is actually your prostate. With proper stimulation it can provide a rather satisfying sensation which is not like a clitoral orgasm in nature. The feeling of penetration, per-se, does not contribute to orgasm, but the massaging of your prostate/g-spot is what becomes orgasmic (at least for me).
That is a rather mechanical explanation, of course, and does not take into account any situational eroticism. The brain, after all, is the biggest sexual organ and is where the seat of orgasm lay. Part of your post-operative recovery will be to re-train your brain to understand the changes and what contributes to fulfillment.
-Sandy
