Chiming in to say that the 7.1 betas, but even more specifically b3 have made the iPhone 4 feel 100% better to use than before. I've been using 'reduce motion' since it was made available and just right now tried with it off (aka fly-through animations on) and they feel just as fast as my GF's iPhone 5. Normal beta kinks aside, it's night and day using an IPhone 4 compared to the stable releases of iOS 7.