For all intents and purposes, they are the same. But if you run different speedos back to back, you will still see a difference in power delivery. Run a Tekin RS back to back with an LRP SXX v2, and even though their final output will feel about the same, the LRP produces a much better "feel" in its delivery...
Better delivery means better control, better control means more confidence, and more confidence means faster lap times.