[Manga] Favorite Pokemon Special/Adventure arc?

We've had many arcs of the Pokemon Special manga. Fourteen, to be exact. These arcs are, in order:

-Red/Blue arc.
-Yellow arc.
-Gold/Silver/Crystal arc.
-Ruby/Sapphire Arc.
-FireRed/LeafGreen arc.
-Emerald arc.
-Diamond/Pearl arc.
-Platinum arc.
-HeartGold/SoulSilver arc.
-Black/White arc.
-Black2/White2 arc (which is still, somehow ongoing to this day due to multiple hiatuses)
-X/Y arc.
-OR/AS arc.
-Sun/Moon Ultra Sun/Ultra Moon arc.

Of these many arcs, which one is your favorite and why? And no, there's no Let's Go Pikachu/Let's Go Eevee! arc in Pokemon Special yet.

I haven't read anything past BW, but my favorite so far was RS. It just felt more emotional than the others, IMO. I'm also a sucker for romance anime/manga (despite not being a romantic myself).

I'm surprised I didn't like GS more, given that's my favorite Gen.