[Opinions] Re: Jane or Jill?
I like them both about equally. And I think they're among the names that work for any age at all, from newborn to great-grandmother.
I'd be more likely to use Jane than Jill, partly because Jill can sound dreadfully flatfooted in some people's local pronunciation and partly because I'd probably go for Gillian, with Jill as a nn ... but then you get spelling issues.
I dislike Jayne: unnecessarily fussy, trying to take a modest girl and turn her into a lap dancer. And I can see the point of using Gill instead of Jill if one's name is Gillian, but I'd spell it Jill anyway to avoid having people say Gill as if it was short for Gilbert.