Yup they are safe, as long as the directions are followed correctly. Plus we always felt that being screwed directly into the ceiling was more secure than over the door (even though they provide a thing for that) but it felt a bit loose for us, so we didnt' do it.

My DS loved it - couldn't get enough of it. DD hated it so went in it twice I think.

We also had walkers, because they are good for a small period of time - ie, for a few minutes a day not a few hours! - and used with close supervision.

MIL's always have their own ideas though on whats best for your child