Oral B pro 1000

I just got my first electric toothbrush. Its the Oral B pro 1000, is it good? I don't know. Didn't do my research. My question is that its says it can be kept on charging/docking station and it is "overcharging is impossible". How true is that? Do people actually leave it there all the time? Is that safe? Anyone heard if those things are a fire hazard or if they explode?