All too often Kirby gets a bad rap, until you ask an owner.
In the 20 plus years that I have owned and operated Kirby vacuums I have found them extremely well built and reliable. These products will literally last a lifetime. With parts readily available even the unskilled will find it easy to fix if the need ever arises.
Most complaints that I have encountered regarding unsatisfactory carpet cleaning or diminished suction can be alleviated by setting the brush at the correct height. Having a fresh hypoallergenic bag and making sure that the airways are unobstructed.