The gap between Orthodox Judaism and Reform Judaism can compete with the difference between evangelical fundamentalism and uh...whatever you are. It's a big gap.
It's far bigger, actually. The cultural gap between a secular Reform Jew and an Orthodox Jew is bigger than the cultural gap between an evangelical Christian and a secular mainline Protestant by orders of magnitude in terms of the effect on one's life. If you are an Orthodox Jew, that is who you are on a fundamental level. A typical Orthodox Jew has to live somewhere that's within walking distance of his shul (congregation), in a likely 90%+ Orthodox Jewish neighborhood (due to the prohibition on driving on the Sabbath), wears distinctive clothing that sets himself apart from the rest of the population, and has to constantly interact with religious regulations in determining what to eat, what to say, who to interact with, etc. that they end up in a relatively small world. These issues are doubled when dealing with serious ultra-Orthodox Haredim. To come up with a comparison for Christians you'd need to compare a normal Christian to the Amish.
