My experience of my brother and myself as a pair has led me so far to find that we both use the same method to search for information, but we use different methods to filter it. Quite often we both do the same 'aha!' at the same moment, we both perceive the same things or in the same way, we both love to brainstorm and we're masters of the rapid fire anything. But where we tend to disagree is with our evaluation of the data we perceive. Whilst I tend to look at things from a more sorta communal, practical and perhaps dutiful sorta point of view, he tends to look at them from a more individualist point of view. He takes things personally a lot more and though we're both awful at taking criticism, his reaction is hurt feelings whilst mine is more like curiosity or indignation if I perceive it to be inaccurate; his concern is to be liked, whilst mine is to be accurately perceived, not caring so much whether that then leads to someone liking or disliking me.
And yes, he can be much crueller than me and tends to be able to justify his own behaviour more easily, he can easily shake people off who attach to him if he doesn't like them or find them interesting, whilst I tend to feel a sorta duty to stick with them and work with them and stuff, regardless of whether I like them much.
I can't say how much of this is ENTP/ENFP and how much is just me and him.