Re: 50 percent more powerful
I'm pretty sure they have said the Xbox One OS's reserve 3GB of memory and not 4. I also think the PS4 reserves 3/3.5GB so pretty much the same.
Personally I don't care about clock speed, transistor count etc and who has the biggest/fastest numbers. I only care about my games playing and looking great, if either of the systems can do that, then I'll be happy.