Very popular in Japan and the charging time is very little. You just pop the battery out and carry to the nearest place with a power point and plug in for half an hour or so while you have some tea and ramen. I've seen the odd zero whooshing around here in Oz. A rider near me uses one daily and transport around the city. Seems reliable and he's had it a few years now. We will need a serious drop in purchase/replacement costs for batteries to really take off I think. In cage terms, it amazes me that people will spend an absolute fortune on a Prius which has massive battery replacement costs and upfront purchase price but is not much more economical (actually in real terms, much less economical judging by the taxis I've been in) than a small 4-cylinder petrol from Japan.