I like the quality of the sculpt work on HT's hair, but NECA got the overal silhouette of his hair better. I would agree that NECA's basic head sculpt with the refined sculpting of HT's quality with HT level paint would be the ultimate. This EB head is very close to being just that, but like a-dev said, for every thing that a company gets better than another, the latter gets something right the current one didn't.
There's been a progression.
Kenner > Sideshow > NECA > Hot Toys > Enterbay
Each company over time turns out a better looking overall piece, but, they have all still been flawed. It would be great if someone finally enhanced the flaws of the predecessors and retained the things done right.
Well since you've done it I'll admit that my perfect T2 Arnie headsculpt would borrow heavily from the Neca one. You get jumped on for saying things like that around here and I fully expect it to happen but ___k it. If you could somehow put the front-on face of the EB head into the Neca sculpt, retain all that worked with the Neca, and give the whole thing a HT (and hopefully EB) quality finish and paintjob then IMO you'd have the perfect T2 Arnie, no complaints whatsoever.