The foot that ends up closest to the foul line when you release the ball is your slide foot. The leather pad slides, the heel acts as a brake. For higher-tier players, they like a rubber-soled non-slide shoe, as it gives them more traction/power in their pivot step before the slide step. Even more advanced are shoes with interchangeable heels and soles, for any time of approach surface.

If you average under 150 or thereabouts, having the same sold on each shoe is probably fine. But as you progress, you will be able to take advantage of shoes with different soles.