If a Kobo charger is best for you, that's good. My reasons for liking the cable approach are:
1. I've got a drawer full of cables, including these two, but I'd never tried them together. So it's free, which is my kind of solution
2. It seems that the 2 amp output needed for a straight Vox charger doesn't apply to this solution. I've been charging mine for the last week on a Kindle keyboard USB charger, rated about 800mA. It also charges off a cigarette lighter USB adapter (rated 1A) from the 12V electrics in my car and my boat. I've even charged it off a USB hub, although I've not had the courage to try a USB port on my laptop, in case it overloads it.
3. With a few other cables, which I've already got for other devices, I can charge everything off one small Kindle charger, rather than carry multiple chargers