They are a fundamentalist sect of Christianity. Yes they are annoying when out preaching, but tell them not to come back and they won't.
Unlike the Catholics, they aren't responsible for some of histories greatest atrocities. In fact, they are a very peace-loving people who live simple lives, centered around strong family values and honesty in all things. If Jesus wouldn't even let Peter defend him with his sword, what sense does it make that mainstream Christianity has caused or condoned every war in the last two thousand years?
Those who say that their interpretation of the bible is wrong clearly don't study history. Things like the Trinity, the date of Christmas and the differentiation of the clergy/laity don't know that those things were added by the council of nicea 400 years after Jesus died. That council was lead by emperor Constantine, who was a pagan until the day he died. He added those and other rules to ease Rome into converting.
Of all the religious nutjobs out there, they are about the most harmless. I'm not saying I'd ever rejoin, but that's just because I hate religion. Just about every witness I know is as nice a person as I could ever hope to meet.