Both sound like awesome parties. At this point, I'd have to give a slight edge to Alice though. You could always combine it, make it a masquerade Alice in wonderland party/a dark themed Alice in Wonderland.

Hi - I like the sound of the Masquerade - more intriguing!!

Have a look at some of the sites to get some ideas and inspiration in having a Masquerade Theme :)

https://suite.io/shelley-frost/37h32np

http://www.pinterest.com/explore/masquer...

http://www.partysuppliesdelivered.com/pa...

These dresses are quite unusual :)

http://favors-decorations.partysuppliesd...

http://www.shindigz.com/party/masquerade...

I love this dress - it would also look nice with a pink mask or a black one or even a purple one - it is very pretty, I love the colour and the style and it looks very feminine - all in all - a beautiful dress - great for a masquerade style party :)

http://www.shopindress.com/a-line-strapl...

You will find some similar here:)

http://www.shopindress.com/masquerade-dr...

Masks

http://www.aliexpress.com/cp/masquerade-...

http://www.dhgate.com/wholesale/masquera...

If you went for the pink dress you could go for a colour theme i.e. pink and black or pink and purple or whatever colour you choose for your dress and mask - then go with those for your colour scheme.

You can also co-ordinate your cake in the colours you choose - have a look at these :)

https://www.google.co.uk/search?q=masque...

Anyway, I hope you get some ideas and inspiration from the above and have a great Sweet 15 Party - happy days ahead :)