Discussions like these tend to focus to much on the distinctions between the two religions -- as if they are simply two different options for anyone to accept. That's really not the case. Christianity and Judaism are philosophically at odds with each other for the simple reason that they are closely related in a way most of the people involved in these discussions never articulate well. Christianity is the fulfillment of Judaism, which makes them inseparable on one level but incompatible on another. From a Christian perspective, Judaism is anachronistic at its root -- meaning it exists today outside of its appointed time and place in history.
Shapiro does raise an excellent point, though -- when he points out that variations among various Christian sects make it hard to use any of them for comparison to Judaism.
Fitting the two Testaments together is something that requires a lot of insight and has a lot of pitfalls.
The Christian groups who have gotten closest to an integrated view, such as our modern Messianic Jews, would be a good place to start. But it is also necessary to observe, with due glory given to Him, how God works in the world through both Christians and Jews. The ultimate conversion of the Jewish people is something that is still a future event.
Christians believe themselves the fulfillment....
And what could be more vexing than the eternal Jew flying in the face of that belief.
I’d wager many, many more intelligent Christians have compared Christianity to Torah-true Orthodox Judaism and have converted, than Orthodox Jews have converted to Christianity.