The WFDS-24 is a 1 HP uprated pump which is equivalent to a 3/4 HP full rated pump (same as the Challenger) but with the addition of two speeds. So this pump will likely be more efficient at full speed but use about 1/4th the power at low speed. As for the controller, most will support two speed but if it doesn't then a simple low cost two speed timer could be used to control the pump.

I don't know the stats of your pool but I have 21k gallon pool with a 1/2 HP 2 speed and during the summer, I run high speed for solar with a vacuum cleaner for 2-4 hours per day depending on solar demand and use the low speed for general circulation for 3-5 hours per day depending on time of year. The cleaner and skimmers work much better at high speed but I really don't need much per day to keep the pool clean.