In my experience, the INFJ-ENFP interactions have this unreal quality. We will arrive at the same conclusion on intuition alone, but whenever we analyze the methods we employed to get there, we realize they are truly different. Mutual fascination ensues. Lots of "Wow....how did you....you're a genius". Lots of giggling too and playing too! Its like they both turn into children. Another advantage of the ENFP is that unlike the ENTP, the ENFP is very much people-oriented and does not mind spending all their energy in trying to figure out every quirk and make the relationship thoroughly conceptually and emotionally perfect. Figuring out others is one of the things ENFPs do best and the INFJs are an excellent psychological puzzle and playmate.
The major advantage ENTPs have is their Fe. This is significant because ENFPs and INFJs are both feeling dominants, feeling is very important to both, Fi will be pitted against Fe, and by god, it can be bloody - here is where you will find INFJs saying ENFPs are too dramatic or ENFPs being dissapointed whenever they finally get through their heads that the ultra-egocentric INFJ does not feel such ethereal connectedness in everything, which is very important for the ENFP, thus shattering many of the ideals that sustained the relationship in the first place. In my opinion this has nothing to do with balance, the ENTP might provide a pleasing romantic narrative / story because once the introvert peels the layers of the ENTP, the INFJ will find at the core something that he/she can relate to, that is Fe instead of Fi. INFJs are not that adventurous to pick something so radically different in a partner.... Fi will only confuse them.