I have my preference (I think :)) but am wondering about yours and why you like it.
Thanks!
Mine is [name]Vivienne[/name]. They’re pronounced differently to me ([name]VIV[/name]-ee-in and viv-ee-EN) and I prefer [name]Vivienne[/name]'s pronunciation.
I prefer [name]Vivienne[/name]. [name]Vivian[/name] is still a beautiful name just a little more tame than [name]Vivienne[/name]. [name]Vivienne[/name] is a little more glamorous. And I love French names.
I prefer [name]Vivian[/name]. As the pp said, [name]Vivienne[/name] looks like [name]Vivi[/name]-ENNE, and I just find that a little pretentious on a non-French child. Plus I usually tend to like the most streamlined version of any name. I could go for [name]Vivien[/name] just as easily, though.
[name]Vivian[/name] is my third favourite girl’s name and I adore this spelling. The [name]Vivienne[/name] spelling makes me think of [name]Angelina[/name] [name]Jolie[/name] a little too much. Plus I think the [name]Vivian[/name] spelling is sweet and simple. That said, they’re both absolutely stunning names and any girl would be lucky to have either 
I prefer [name]Vivienne[/name]. [name]Vivian[/name] looks incomplete, like a bastardized version of the previous, and I would pronounce it [name]Viv[/name]-ee-anne, which I am not too keen on.
[name]Vivienne[/name] all the way!
The spelling of [name]Vivienne[/name] looks prettier to me
[name]Vivienne[/name], it looks more feminine.
[name]Hi[/name] 
I prefer [name]Vivienne[/name] as, like other posters, I prefer the pronunciation (viv-ee-EHN over viv-ee-in) and feel it is more feminine and elegant. I think [name]Vivian[/name] may be the masculine? Like [name]Adrian[/name] (m) and [name]Adrienne[/name] (f).
I agree with [name]Daisy[/name] about the different pronunciations. Anyway, I prefer [name]Vivien[/name] to either, which has been on my list for a [name]LONG[/name] time. Although they are both lovely, [name]Vivian[/name] looks a bit masculine, whilst [name]Vivienne[/name] is too frilly for me. [name]Vivien[/name] has the same simple, vintage feel as [name]Vivian[/name] as well as the glamor and sophistication of [name]Vivienne[/name]… only it’s more streamlined and is accessible on a child, and it could use either pronunciation (though I prefer [name]VIV[/name]-ien to viv-ee-EN)
I like [name]Vivien[/name]. Feminine, but not as frilly. I usually like frilly names but I just think [name]Vivien[/name] is much more sophisticated than [name]Vivienne[/name]. [name]Vivian[/name] is nice too, but [name]Vivien[/name] is def my favorite.
Honestly, it is a nice name either way, but I think anyone who plans to insist on the [name]Vivi[/name]-ENNE pronunciation is kidding themselves, at least in the US. That cadence is simply not natural to the American accent.
I very much prefer [name]Vivian[/name] or [name]Vivien[/name]. After all, those are the original English spellings of the name. [name]Vivienne[/name] is just the French version of the English name that came after. I also agree that [name]Vivienne[/name] is rather pretentious for a non-French child and may also pose some pronunciation problems. Also, that spelling feels branded by Brangelina to me.
I definitely prefer [name]Vivienne[/name]. I love French spellings/ pronounciations and names in general so that is the main reason. I do think it is more feminine and yes frilly, but I like frilly
My 2nd choice would be the [name]Vivien[/name] spelling because I like old Hollywood glamour ala Viven [name]Leigh[/name].
I prefer [name]Vivienne[/name] - I like the way it looks and I prefer the -enne pronunciation, as unlikely as it would be to actually get in the US. [name]Vivian[/name] doesn’t have the same feel to me, which is odd, because it’s the same name.
[name]Vivienne[/name], i think its mostly because like the way longer names look just like i prefer [name]Juliette[/name] over [name]Juliet[/name].