I have their strut suspension and power rack in my 68.
The steering is great, really precise although the turning circle is a bit larger than stock.
ride quality and stability is great , their newer struts far better then their older sets The new sets allow you to provide spring tensioning (ride quality ) seperately from the ability to lower the vehicle. I have the 2x piston PBR setup and it works well after changing to more aggressive pads.
Agree about the after sales and lead times but have driven other club members mustangs and compared to theirs mine handles and steers like a new car.