Ego, yes, that's illusion in Buddhist terms.
Distinctions, no, though I would have to wonder which distinctions, really, wouldn't you? Some would probably be spurious, some not.
Even the joy you've tipped the hat to in your reply, gets trumped, in that it invariably exacerbates suffering. While the Christian view acknowledges the profundity of suffering, it doesn't seem to be the reigning principle. The Cross gives way to Resurrection. This is simply a difference I see, between these two systems of thought. One seems, in spite of bright spots, essentially pessimistic. The other, in spite of drearest valleys, essentially optimistic.
I think we may be talking past each other here.
The cross and redemption through Christ's suffering is a solution, as I understand it, to the suffering of the world and of humankind in the state of original sin within the world, isn't that right? This is the state of the world within the frame work of at least much of Christian theology. The solution that Christianity offers — the relief from the suffering of the fallen state, as it were — is salvation and grace through the intervention of a personal savior in the form of Jesus Christ. If I have the details wrong, please forgive me here; I'm not trying to dispute the theology. The muslims believe in bodily resurrection and the Jews have at times believed in it as well, though I think the belief is probably not a large part of modern Judaism. It certainly was in the tenth and twelfth centuries C.E.
The point is that there is essential agreement about the place of suffering in the world between the Buddhists and the Christians, at least to my mind, about this thing. Where there is disagreement is about the solution. In the various Christianities, the notion has generally been that the acceptance of Jesus as one's personal savior and a sincere attempt to bring one's life into line with that commitment is the solution to the suffering in this world
"in the sure and certain hope", etc. While there has been original sin, a belief in The Christ may save one from the fires of hell, whether experienced in this world or the next; or, as may be most likely, both — at least within that framework.
The Buddhists accept this suffering as the condition of life, and attempt a different solution. I believe it inferior in no way to the Christian solution. Both Christianity and Buddhism are pessimistic about the native state of humankind. The Christians say it is original sin; and any attempt to suggest that original sin is essentially optimistic would run against a considerable amount of Christian theology. The Buddhists say that Life is Suffering. You may see these as vastly different statements; I see them as identical.
Both points of view offer solutions, good solutions though not identical. The Christian solution is more dependent on faith. The Buddhist solution depends on actual practice to produce personal change; to some extent it can be measured scientifically in the physiology of long term Buddhist meditators. The readings are distinct from long term yogic meditators, by the way, but are still measurable. This doesn't mean better, but it does mean something is happening that fits the description of what the Buddhists say is supposed to happen.
I know long term believing Christians who seem to have gone through similar transformations, by the way, though I wouldn't know how to measure them. I would suspect that you know them too.
I would suggest that you may be hasty in suggesting pessimistic and optimistic designations to the suppositions of the two world outlooks. If religion in general didn't solve some sort of problem for people in general, I would assert that it would not have so many staunch adherents willing to fight over fine points either to prove themselves right or to prove somebody else wrong. Or both.
Sincerely, Bob Kaven