Here's a Pew Center report on something I actually did a research paper on years ago but -- true story -- accidentally deleted after months of work. I focused more on whether a sudden versus gradual experience led to more extreme views, both religious and political. But the basic idea is the same. See the table below:
I argued that a sudden conversion led to more extreme political views. The data only barely supported my thesis and then, like an idiot, I accidentally deleted all my work. Given the weak support, I didn't try to recreate the manuscript. No great loss.
The Pew results are better, but then again they're linking conversion to religious behaviors and attitudes. That's a much easier direction to go. Obvious, yes, but important. As a practicing cradle Catholic I've seen this myself in converted Catholics who tend to freek the rest of us out with their enthusiasm.
What's it all mean? Converts are more energetic, more enthusiastic. More narrow minded? Dunno, but that would kinda follow, I guess, as they develop a religiously-focused tunnel vision based in their faith. But maybe it depends on the particular faith they have converted to. Luckily, Pew breaks it down by faith/affiliation and the same religious measures and this conversion zeal effect seems to hold across most faith traditions. Go here for the table with that breakdown.