This is a clean in-family decision. Both are Simucube 3 bases, so they share the chassis, the class-leading build and Simucube Tuner 3.0 - the Sport is not a cut-down design, just the lower-torque rung. It puts out 15 Nm and scores identically to the Pro on build and software; the Pro's edge is more peak torque and the single highest fidelity mark on our rubric.
So you are paying $200 for headroom and the last increment of signal. Fifteen Nm is already a serious amount of torque - plenty for the vast majority of drivers and cars - so the Sport covers most people comfortably while keeping the full SC3 refinement. The Pro makes sense if you specifically want more torque on tap, or you are the sort who will notice and value the top-of-the-scale fidelity it adds.
For most buyers I would take the SC3 Sport and enjoy that it delivers nearly the whole Simucube 3 experience for less. The Pro is the pick when you want the ceiling of the line and the extra torque earns its keep for how you drive. Either way you are on the same platform, so nothing about the choice strands your wheels or software.