I suppose you are hoping for a definitive answer. We all hope for definitive answers in almost every area of life - in fact, it is that hope for certainty that is the primary cause for fundamentalism in all its manifestations. Benjamin Franklin famously said that the only two sure things in life are death and taxes. I would add birthdays to that list, except that in truth birthdays are merely markers in our march toward death and so are implied in death. As to taxes, the only certainty is that they come due - there are those who refuse to pay them, so perhaps they aren't certain either. That leaves us with death.
Is Buddhism a religion? I suppose that depends on how one defines religion. I heard an interview the other day in which the person being interviewed defined a religion as a belief system that looks for outside intervention from a force more powerful than oneself, an intervention that rescues us from an unpleasant circumstance. That perspective hadn't occurred to me, so I spent some time reflecting on it. How does it impact Christianity? If one follows the traditional Christian path and believes that Jesus "saves" us from hell, then Christianity is a religion. On the other hand, for someone like me who can no longer believe in a hell from which humanity needs saving, I suppose it could be said that the Christian path is spirituality, not religion.
Some people are quick to point out that the root of the word religion, "ligare" means "to bind [back] or to tie." That certainly has been the experience of religion for many people, but I have to ask whether or not that remains a valid goal. Is the purpose of religion in our lives to control us, or to keep us from doing something that we shouldn't? Is that even desirable? Many of us have, indeed, felt constricted by religion - not in the sense of being kept from doing the things we ought not do, but in the sense of being kept from achieving our full potential. In my experience, spirituality tends to encourage us to achieve our full potential and sees us not as some kind of animal that needs to be tamed but rather as a human being with a conscience which tells us when we cross a line of propriety.
So we return again to the question of Buddhism as religion. If we accept the definition of religion offered above, that religion looks to an outside person or force to rescue us and also binds us back from doing the things we should not do, clearly Buddhism is not a religion. Buddhism places the responsibility for our self improvement project squarely on our own shoulders - right where it belongs. While Buddhism doesn't rule out the possibility of a God, it does hold that we are the agents of our own salvation. I value that emphasis on personal responsibility and the lack of an outside agent who forces us to misbehave. When Mara, who might be understood as temptation, comes to visit we are encouraged to treat Mara with compassion. We treat our temptations with compassion rather than attempt to deny they exist in order that we might appear holy to our friends. Can we make peace with ourselves? If we can, then surely salvation exists and we are saving ourselves.
How does this square with the Jesus experience? Truthfully, Jesus laid out a path for his followers to walk and was critical of the religious and political leaders of his day who sought to convince the people they were beholden to the leaders themselves for their salvation. There is no small amount of irony in the truth that as the Christian religion grew it tried to convince it's adherents that they were beholden to the Christian religious leaders for their salvation. I believe Jesus would have opposed that behavior as much in the Church that claimed to follow him as he did in the Jewish leaders of his day.
Is Buddhism a religion? Only if you make it one by distorting the teachings of the Buddha. Is Christianity a religion? Only is you make it one by distorting the teachings of the Christ.