Interesting I don't think we have any of these churches in Scotland. I have considered attending a closed brethren church, but the issues may be similar, in that it seems they expect you to have an invite. They don't like people just to turn up.
Things I tend to look out for include any literature they have on offer. Plus how involved are women in the service. And find out how the money situation works: it's always interesting to work out who among the congregation is being paid for their work at the church. Especially at Adventist meetings this can be quite interesting to work out who is the paid pastor an who work voluntarily.
Before I attended any other church I had the impression that most conservative churches restricted women as JWs do, but this has not been my experience. In the Mormon church women speak from the platform, say prayers, lead singing. Among the Christadelphians, where the women wear hats on Sunday, women can lead midweek meetings, say prayers and so on. In fact I've not found any group as restrictive in terms of what women can do as JWs. It would be interesting how Iglesia Ni Christo compares.
In particular it's got me to wondering: why are JW women not allowed to offer prayers at the meetings? This is a restriction no other group has that I've visited. Is there a Bible justification for it? They use the scripture that says a woman should not teach the congregation. But prayer isn't supposed to be teaching, is it? I wonder if there's ever been a WT explaining why sisters are not allowed to offer prayers at meetings.