"This is essential if you want to use the 8878 Power Functions Rechargeable Battery Box. I can understand why 8878 doesn't come with a charger - you might want to buy multiple battery boxes but don't want another charger every time (indeed, I have three batteries but only one charger). But this is outrageously expensive.
Five for Play Experience and recommended, simply because it lets you use 8878 - which is much more convenient than the 88000 AAA Battery Box. One for Value for Money because of the very high price."