A lot of people think that smartphones manufactured by Apple are expensive toys and others offer more powerful hardware for the same price. However, hardware specification will not tell you anything about the performance, because this depends also on optimization of the operating system.
Unfortunately, in case of Android smartphone, the operating system is written by Google and the hardware is produced by other companies (e.g. Samsung or Huawei). Therefore, we can compare performance provided by different devices by running the same benchmark. In case of mobile devices the most popular is AnTuTu Benchmark which is available for Android and iOS devices. Numbers do not lie, it occurs that the most powerful smartphone released in 2015 is iPhone 6s which gained 43% more points than Huawei Mate 8 and 61.5% more than Samsung Galaxy S6 Edge+. If you wonder whether you should buy iPhone 6s version, then you should know that it is 64.6% more powerful than iPhone 6.
These data were collected by 6.0 version of AnTuTu Benchmark, which works differently than 5.0 version. The presented scores are averages of at least 500 data sample of each device/chip model.
Remember to not compare results from different version of AnTuTu Benchmark. If you are interested, then here is an example table which shows what the differences are.