It appears that the two varieties are actually very similar, with the only discernible difference being the lack of green colouring, and the mint flavour. Not that that is a bad thing - the swirls of white and milk choc are rather mesmerising to look at, and better looking that the green and milk combo.
The bar itself is quite sweetly scented, and seems to have a little praline note, though it contains no hazelnuts. The design is classic Kit Kat, with thin layers of wafer separated by a cream, and then covered in milk chocolate, with the decorative 'white choc' swirls across the top.
Like classic Kit Kat, it is, well, classic. Aside from the appearance, there isn't much to discern it from the original; I couldn't taste much of a difference. At least the Choc Mint Whirl had the flavour working in its favour; Choc Whirl is a bit uninspired. But hey, it still tastes good!
Score: 4 out of 5 jelly beans
Nestle Kit Kat Choc Whirl is made in Australia. It contains milk, wheat and soy, and may contain traces of peanuts and tree nuts.