Energon is almost a reverse of Armada. It starts strong but faceplants hard. But whereas Armada turns things around halfway through the show, Energon's "good part" ends after like five episodes.
I'd argue that Armada ends on such a high note and in such a way that a sequel isn't even needed?
Galvatron sacrifices his life because he realizes it's the only path to peace. Optimus abandons the Matrix to symbolize he's no longer the Autobots' leader, and will try to lead a united Cybertron. Unicron is destroyed.
The whole thing has a sense of finality to it.
Energon's opening does a decent job picking up some of those plots and exploring them if they were to be taken further, but once Megatron mindwipes everyone on the 'Con side and undoes all of their character development... it's just a terrible show. It also runs out of plot halfway through and just starts circling back on itself.
Cybertron is a really fun show. More polished than Armada, but I prefer Armada. Still, Cybertron is an enjoyable ride and has some pretty fun highs.
Thing is Cybertron is best enjoyed as a stand-alone thing. If you watch it with that mentality you'll enjoy it more. Trying figure out how it can possibly connect to Armada (and Energon, if you must acknowledge it) is an exercise in madness.
So I personally enjoy 2/3 of the UT. A bit more if you tack on the start of Energon before it goes... downward.
I was also 14 when Armada started, was way into dubbed anime at the time, and I already liked Transformers, so it was easy to get into it I guess.
Still, I'll go to bat for...
Armada's kids being the most realistic depiction of human kids in Transformers animation
Armada Starscream's whole arc, including his friendship with Alexis
Rad's dad being the realist MFer in the room
How Unicron is handled as a Lovecraftian cosmic horror
The best Optimus Prime death in the franchise
The mood and tone of the Unicron Battle arc
Nemesis Prime (he's so hot right now)
Armada having the best version of Sideways and the only one that really took advantage of the faction swapping gimmick
The best Optimus v Megatron fight (well it's technically Galvatron but whatever) in the franchise
Galvatron's sacrifice
I don't feel like running down Cybertron but it's just a fun show