My DH was one (his mum & sisters still are, but his dad never was), and it has been very interesting learning about what he grew up with. I wouldn't say he & his family were necessarily the strictest, but they do witness every chance they get. Not at me, much, which is good. DH even got a cryptic text message from his mum on his birthday last year! "So what's it like being 34years old??" - we reckon his mum is softening in her old age.

I don't pretend to know anything about the religion specifically, but we did have a spectacularly humerous conversation about creation vs evolution.

Generally, I find them to be nice people, and if you choose to put a line in the sand re: witnessing, it is respected. Technically speaking, I know that DH is meant to be outcast from the family & 'church' for leaving. They can only technically speak to him if they are trying to bring him back to the fold. DH's best mate has had a terrible time (years!) coming to terms with this with his own family - who are a lot stricter than DH's family.

ETA: I think it's really good to learn about other religions in a non-judgemental way. Good for you for starting this thread.