My question on Messianic Judaism was closed on this site, stating that it is not Judaism. Is this the common position of all branches except Messianic Jews themselves?
Yes, this is the generally accepted position of all branches.
Here is an article, written by a member of the Jews for Jesus movement itself, pointing out how Jews reject Jesus across the board. The article specifically mentions how even the Reform and Conservative Jews reject messianic judaism as being a legitimate form of Judaism. Likewise, the Israeli Supreme Court ruled that the "Right of Return" which allows all Jews to automatically be eligible for making aliyah, doesn't apply to messianic jews. While the article is ultimately trying to argue that Jews should accept messianic judaism as legitimate, it clearly shows how the movement is not currently accepted by any major branch of judaism.
For more information about why Jews don't view jesus as the messiah, see here.