Pretty good is an understatement. EXP Share now has more Exp. yield than a Lucky Egg (unless it also gets improved; and speakin' of, imagine if a Lucky Egg[s] stacks with an EXP Share... !), all without the hassle of switchin'. This is a godsend for level grindin'.
I can only imagine the breedin' adjustments will be quite good as well. Every Generation has introduced mighty-useful things to make breedin' specific qualities all the easier.
Where the heck is Ragtime?
Is Classical Music really put with Dragon type?
I don't think Game Music would be under one category.
So I would be a Flying uh something else, I like too much.
Although, I think Jazz is more like Water. Can be slow, can be fast, it flows, bends, and is flexible.