I dunno where you guys are getting high Fe from [MENTION=30122]Brain in a Jar[/MENTION]. They seem like they have a healthy tert Fe.
Y'all are crazy. Every time someone has social prowess, someone shouts ESFJ. Other types can be nice, friendly, and people oriented too! The trait is not FJ exclusive!
I'm not ruling out ENTP, it still seems like a good possibility.
I know it looks like we're ganging up on him but it's sort of a rite of passage for members and I think a lot of us will be called out at least once in our time here; it's healthy to consider other types. Maybe he already has considered ESFJ and decided ENTP was a better fit--if so, good, if not, I think ESFJ is worth looking at. They can "vibe" similarly to ENxPs, especially the "intellectual" ESFJs. Quotation marks used not because I think intellectual ESFJs aren't the norm, but because it's a facet of their personalities that isn't always at the forefront and often goes overlooked as a result. [MENTION=10082]Starry[/MENTION] called ESFJs the people's ENFP. Two different letters misleads us to how similar they can be, that similarity can also present itself with ENTPs.
Either way I think there's a lot of Ne usage as I see a lot of pattern recognition and definitely a capacity for trans-contextual thinking with [MENTION=30122]Brain in a Jar[/MENTION].
Fe also apparent, but is it the finely tuned dominant Fe? Difficult to tell, maybe after I've seen more of his interaction style.
More difficult to tell which introverted functions he uses, but he seems to be a taxonomist (not in the narrow sense), so the Ti might be strong with this one. Fi taxonimists certainly exist as well, but in a very different flavor, something that would be interesting to discuss, a Fi taxonomy vs Ti taxonomy thread perhaps.
Would I say ENTJ? I think other ENTJs would be a better judge. There's something about them that I can't quite put my finger on, but it's in most of the ENTJs who still type as such on this site. I don't see this unnamed quality in ENTPs so much, nor do I see it in Brain, but I don't know him as well as the other ENTJs yet. Maybe that facet is simply invisible to me. Or maybe he isn't one

There is a playful side to ENTJs, it's just a bit more restrained and clipped than what I usually see in ENTPs and ESFJs. It seems like many extroverts think they're an ENTJ at some point, and I wonder if it is due to a widespread misunderstanding of the type, poorly written type descriptions overplaying the E and J whilst failing to convey the NT element, or a combination...
Edit- sorry for being so vague