I didn't watch the whole iPhone vs Galaxy speed test video. I am sure the iPhone multitask better, since Galaxy phones are more aggressive at RAM management, though I don't see this (with the improved s7 series) really affecting the day to day use of this phone.
I did watch enough to see that you can't really take that guy's video serious. Both phones need to be fresh off a factory reset. Some of his iPhone apps opened to where he was last using them, while several Android apps appeared to open for the first time, such as temple run. It's not even clear if he cloaed all background apps.
Overall, I don't really care. Phones are plenty fast today, even low end Moto G exhibit a fluid and fast experience. I just don't like experiments/demonstrations done incorrectly and not controlled for variables. I guess it's the scientist in me.
I guess I could theoretically do this test with my wife's phone, but I don't she would let me do a factory reset, etc.