I feel like the Og Ultraman always suffers when it gets into the battles compared to the other stuff. There are some later episodes that are
fantastically shot throughout, but then the giant Ultraman battle just drags everything down. Later on they kind of stop doing overly goofy choreography like that one time Red King was cheering while other monsters fought, or Ultraman acting like a boastful (mime) wrestler in some early battles, but the suit acting still feels oddly goofy and weightless even when they aren't openly going for humor.
UltraSeven is overall more serious, although a few of the battles still fall to goofy stuff. It limits almost all stories to be about alien invasions though, rather than the complete free flow of the original Ultraman, where the only requirement is a giant monster appearing for a battle at the end.
Return of Ultraman generally is serious too and pushes character drama much more strongly than both of the previous series. It also still has a couple of episodes that stand out a lot visually in the middle of the series (and they finally manage to make good suits for quadruped monsters). However, it's also the series where they start giving up on being an actual sci-fi show and become more like standard toku, with many monsters just appearing out of nowhere in order to trigger the episode's human drama, some feeling really forced (like this one time a construction team finds a complete dinosaur fossil and they just want to demolish it to finish their building, and only children and people sympathizing with the children seem to care enough to stop them from destroying what should be a historic discovery). It's also pretty clear the show was running low on budget in later episodes when the entire "Earth defense force" was reduced to five guys in a car. The finale ends up pretty underwhelming.
Then Ultraman Ace is when they completely gave up and it's just a standard toku show, although with some very out there imagery at times. There's now an actual recurring villain behind the scenes sending the monsters and they can appear anywhere from anything, due to their "chouju/Terrible Monster" creating machine. There are many serious episodes, but also a few quite goofy encounters beyond anything in the previous series. Frustratingly, the special team here also often dismisses reports of monsters from their own crew, even punishing the main character sometimes when he wants to lead an investigation but there's no giant stomping around, which makes little sense when they know there's a recurring threat. It also introduces goofier concepts like the "Ultra Brothers" as recurring characters (although most of the time just to briefly give plot devices, exposition or job) and "Father of Ultra"
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I'm only starting Taro so I can't comment on it yet.
