[Kiwami]

I'd be interested to see what someone who actually watched a lot of Ultraman has to say to this; only thing I can tell is that I often hear that Max and Nexus are highly praised among fans.

I only watched X and Orb but both are really, really good. So I wouldn't be surprised if people actually say one of those two is the best.

As far as production value goes I think you have to say X / Orb, not only because they are newer, but the suit work, models and effects are amazing. Even the CGI is on point most of the time.