I don't think you would significantly notice the strut brace in isolation, but when you pair it with the sway bars, coilovers, etc, it makes a difference.
Mine turns in significantly better than a number of others, and that was before I changed all the bushes, and before the under body bracing. It feels unbelievable, and I've had guys drive mine, and be passengers, and they can't believe the way it changes direction.
Sure, its no MX-5, but it's about 800kg heavier, and its designed for people who actually have friends/a life.