The Alpha EVO 12 is a mid-tier value base with the smoothest signal in its class; the SC3 Sport is the entry to Simucube's flagship line, with class-leading build and Tuner 3.0, at twice the price. On our rubric the Simagic leads on value, the Simucube on build.
So this is about whether the Simucube build and software are worth double the outlay. For most drivers the Alpha EVO 12 is all the base they need. The SC3 Sport is the pick if you want into the Simucube world specifically and the budget is there.