So. Much. Pottermore.
Vine and Unicorn Hair, thirteen and a half inches, unyielding.
Vine: The druids considered anything with a woody stem as a tree, and vine makes wands of such a special nature that I have been happy to continue their ancient tradition. Vine wands are among the less common types, and I have been intrigued to notice that their owners are nearly always those witches or wizards who seek a greater purpose, who have a vision beyond the ordinary and who frequently astound those who think they know them best. Vine wands seem strongly attracted by personalities with hidden depths, and I have found them more sensitive than any other when it comes to instantly detecting a prospective match. Reliable sources claim that these wands can emit magical effects upon the mere entrance into their room of a suitable owner, and I have twice observed the phenomenon in my own shop.
Unicorn Hair: Unicorn hair generally produces the most consistent magic, and is least subject to fluctuations and blockages. Wands with unicorn cores are generally the most difficult to turn to the Dark Arts. They are the most faithful of all wands, and usually remain strongly attached to their first owner, irrespective of whether he or she was an accomplished witch or wizard. Minor disadvantages of unicorn hair are that they do not make the most powerful wands (although the wand wood may compensate) and that they are prone to melancholy if seriously mishandled, meaning that the hair may ‘die’ and need replacing.
Longer in length wands are apparently associated with witches and wizards with a flair for the dramatic. Even Pottermore thinks I have a “big personality”