I like both, but [name_f]Margaret[/name_f] wins out for me. It’s so timeless and elegant, and I love so many of the nicknames. [name_f]Maggie[/name_f] and [name_f]Meg[/name_f] are my favorites.
[name_f][/name_f][name_f]Margaret[/name_f] is a timeless classic, with lots of rich history and royal connections. If you hear of someone named [name_f]Margaret[/name_f], you can’t necessarily tell from the name alone how old the person is, as it hasn’t had a sharp spike in popularity over its tenure.
[name_f][/name_f][name_f]Judith[/name_f] is also elegant, and a little more solemn/stoic (in my opinion). The nickname options are fewer. It is less ageless, as people would probably expect that [name_f]Judith[/name_f] is senior/elderly (at least in the U.S.), since it is only on the verge of a comeback with new babies.
[name_f][/name_f]I met a 20-something [name_f]Judith[/name_f] years ago (she was [name_m]German[/name_m], so it was less unusual), and it really made me see the name in a new light. I’ve liked it ever since.