I cut my teeth on vernier throttles, and added one to my extremely squirrelly, aerobatic Hiperbipe. Once you master "the claw" technique they are not unsafe for formation, aerobatic, or pattern work. They are also not optimum for this kind of flying, but large or small throttle movements are not a problem. They really shine for cross country flight however. They stay set where you want them, and its very easy to adjust on the descent to maintain constant manifold pressure.
But as previously posted, to each their own. Each method has strengths and weaknesses and some are more mission specific than others, but personally, I'll fly levers, knobs or verniers without a second thought.