No, personally I find most of them are seeking a personal interpretation of the Quran instead of that imposed on them by their clerics. It normally starts with someone asking difficult questions from the Quran and got put off by the way the question was handled (or not handled) - often an unsatisfactory stock answer with a warning not to ask too many questions.
So, most of them are genuinely seeking the truth & not looking to ‘revert’ to an earlier faith.
Also, it is not so much a ‘Quran’ based reasoning but more a Muslim-based reasoning that is retained. For instance, initially reading the Bible in a rigid literalist manner; seeing the actions/law rather than the intention behind the actions/law.
The Sermon on the Mount for instance is an interesting challenge. While it obviously resonates with them (many would be attracted to Christianity in the first place because of the precepts) but deeper analysis could leave some of them grappling with the idea that it is OK to not follow the written word of the Mosaic Law, which they have been taught have to be followed to the letter, as it is given by God (like the Quran). But eventually they overcome this because true conversion is not just adopting a new religion but also involving a rejection of a previous way of thinking in favour of a Christian one.
Btw, I believe the second largest group after Christianity, would convert to Bahaism, but again no stats. Do you?