I took the plunge after I got hosed by my insurance in the he-said-she-said mess that followed an accident in which my car was written off by an idiot that skipped a red light. Went for a cheap Chinese black box that has worked flawlessly for the year I've had it. Has front and rear facing cameras, and records in 1080. Oldest files get overwritten so I never have to worry about the data card getting full.
For your entertainment, here's a little video it took of a confrontation I had with a taxi driver a while back: (Oh and we drive on the left here!)
https://www.youtube.com/watch?v=ZmAU_LSM1bI