Spa is a pretty good track for low and high downforce cars. Low downforce Eau Rouge, high downforce Pouhon. If it weren’t for the bus stop chicane it would be perfect. Chicanes just ruin the flow of a circuit. See Monza, blighted by 2 of the horrid things.
Red Bull Ring - probably my favourite track overall, elevation change, good for overtaking, flows well, no stupid chicanes. Second half of the lap is just perfection.
I am not a fan of the 2x chicanes clumsily dropped into the middle (how can two chicanes be dumped into the middle you idiot?) of the Mulsanne straight at La Sarthe. Horrible, and I'm fully aligned with young David's disgust.
The chicanes at some other circuits I find fine though - where they are blended in a bit better. The Bus-Stop at Spa - fine. The chicane at Monza is fine (but what idiot made it the first corner after the start line - its always carnage). Brittens at Oulton. Inner Loop at Watkins Glen (which is pretty fast, but still technically a chicane I believe).
Sure they break the original track design flow up a bit, but they can create a real technical challenge / another overtaking opportunity.