I've had them on cars in the past and loved them, it all comes down to how you drive. I was finding on track I didn't like the pedal travel so these things shorten that and tighten it all up, means getting your foot to the brake pedal is a bit quicker. Basically helps set the car up how you want it.
On some cars around town its made them jerkey to drive due to how they work, but you don't really need them around town!