The best helmet is the one you wear and fits well.....Whether helmets actually work is a whole book by itself....
The worst bicycle accident I've ever had was WITH a helmet many years ago.....Didn't do crap.The side of my head hit the curb and my ear was the size of a softball for weeks.Split my upper lip open like a bunny rabbit and knocked out 3 teeth.Had scrapes and bruises all up and down one side.....
Thankfully my helmet was not scratched or broken.....or worn again.....