I am ENTP, I thought I was INTP before.
ENTP = Ne(1) Ti(2) Fe(3) Si(4)
INTP = Ti(1) Ne(2) Si(2) Fe(4)
ENTPs keep more options open (stronger Ne perception, weaker Ti decisions) and are therefore more open-minded
INTPs close options sooner (stronger Ti decisions, weaker Ne perception) and are therefore more narrow-minded. not that they are narrow-minded types, but more so than ENTPs. ENTPs are just the most open-minded of all (Ne)
ENTPs are the idea-generators, more so than INTPs. It is because ENTPs are just more open-minded, keeping more options open, even impossible ones (because you never know).
INTPs shut down impossible options immediately because they are not logical according to their stronger Ti.
INTP ideas are more thought out, ENTP ideas are more fuzzy and vague. ENTPs think they see the whole picture (they do actually), yet they have no clue how to explain it, thus also not how to implemented it (although they think they do, because they "see" it).
ENTPs can go into Ne-trips, which is like a giant idea-high, like a roller-coaster ride. WHOAAWOAOOHOAHAHA NEW IDEA WOWWWW... This can sometimes infect others as well and cheer up people and make the people like the idea as well. It can also be too much for most people and they will think the ENTP is weird and nuts.
ENTPs are most social if they can ramble about their ideas non-stop...then they are more extravert than anyone. but... if they dont have good ideas, they become quite introverted, they then become observers, waiting until good ideas pop, worthwhile of saying. An ENTP will never say or take charge if he/she thinks his ideas at this moment suck, then the ENTP will just shut up and appear introverted. ENTPs also have new ideas when they shut up, because they just always have new ideas, but they just know they suck at the moment they shut up.
it is said that ENTPs are the most introverted of the extraverts. Which is true, until good ideas pop and then it's like they are on fire.
also, in ENTPs the Ti/Fe is more balanced. and in INTPs the Ne/Si is more balanced.
INTPs have such strong Ti, that their Fe is a bit lacking (their weakness: sucking at dealing with people, making them a bit autistic)
ENTPs have such strong Ne, that their Si is a bit lacking (their weakness: sucking at seeing what is there to lose, making them over-optimistic / over-courageous)