I replaced a perfectly good single speed with a new Pentair Inteliflo VS 011018. It is so quiet and cost a fraction as much in electricity to run. But even if it never saved me anything on my electric bill, I would still have a VS pump. The ability to setup a daily program with the prefect speed for each task, makes a VS pump worth it's cost. I replaced my old pump with a much more powerful 3 hp pump. But not a problem since you can set any speed or power you need, and even if you worry about someone turning to on at full power, you can even set a maximum speed to prevent that.
My pump comes on, cleans the pool, drops down to the correct speed for my SWG to chlorinate, then slows further for just filtration and circulation, if heat is called for and available at my solar, it speeds the pump to feed the solar panels, and slows back down when finished. All the speeds and changes are programmed right into the pump and happen automatically without needing any automation system (except a solar controller to work the solar valve and trigger the preset solar speed on the pump).