They suck, according to Sam Michael of Williams.
"Chicanes are the bane of F1. They destroy any chance of overtaking because the guy in front can just go into the apex, protect the corner and not hurt his exit. You can't do that with a hairpin. If he protects on a hairpin he loses on the exit but with a chicane he just backs the guy up, sorts himself out and off he goes again. They should just ban chicanes."
Wow. Welcome to 25 years ago...fans have been saying this forever. Now all we have to do is redesign just about every circuit on the planet.