Or [name]Guinevere[/name]? I really like Arthurian legend names…
I think both are usable. But people might have problems spelling [name]Guinevere[/name]…
I think [name]Isolde[/name] is usable but [name]Guinevere[/name] would be a bit much up front. Most people are a lot more familar with the character of [name]Guinevere[/name] so if you used it, I would suggest putting it in the middle.
I don’t see why it wouldn’t be, personally I prefer [name]Isolde[/name] to [name]Guinevere[/name] 
I think they’re both usable and beautiful. I’ve met two girls named [name]Isolde[/name], they both loved their name (both in Norway though, and it’s less inclined to be misspelled over there). [name]Iseult[/name] is an alternative.
Bellicent, [name]Elaine[/name], [name]Rhiannon[/name], Niniane, Nimue, [name]Viviane[/name], Nyneve, Lyonesse, Laudine, [name]Olwen[/name], Blanchefleur, Caelia, Heliabel, Lunete/[name]Luned[/name], Igraine, [name]Enid/name, [name]Morgana[/name], Ettarre are other beautiful names from the legends.
I want to love [name]Isolde[/name] but i always just hear “Is Old” [name]Guinevere[/name] is lovely though.
I think both are perfectly usable, though [name]Guinevere[/name] may run into some spelling issues. I personally prefer the shorter [name]Isolde[/name], or rather the [name]Yseult[/name] variation.
I see teasing potential for [name]Isolde[/name] (because it sounds like “is old”). [name]Guinevere[/name] is lovely, and a close friend of mine has the mn.
I like both, but [name]Isolde[/name] may like others have said have some teasing potential.