IQ test results will vary somewhat. But the best, professionally produced tests, conducted under proper examination conditions will produce fairly consistent results.
IQ is actually a fairly good indicator of intelligence in the ways that should matter most. Objective reasoning, application of logic, speed of thought, and focus are all necessary attributes of successful operatives in the worlds of business, public services, politics, or the military. People possessing these attributes to a higher degree will tend to have the capability to take the actions and make the decisions which lead to successful outcomes.
Unfortunately in today's modern world, IQ and the attributes which it measures are under attack from those who consider that other more woolly alleged forms of intelligence are as important, if not more important. The most notorious of these if of course our old friend "emotional intelligence", which let's face it is really the manipulative brown-nosers' charter.
Most people do not want to live in a highly dog-eat-dog world, and people issues do matter. However if sound logic and reasoning in decision making is to be constantly contaminated by considerations about relationships, team-building, diversity, anti-elitism, and political correctness, then the world will not become a better place to live in, in the longer term. Everything will tend to reduce to the lowest common denominator.
So I say - long live IQ.