I originally posted my thoughts back in 2012 and I don't think i've changed much since then. Maybe the Dream arc has come to top over the Dark Kingdom arc for me tho. xD

Dream is my favourite one. It had the best portrayal, as far as the manga could get. The Inners had some slight development when they each obtained their Sailor Crystals, and I also felt the events that happened that led them to obtaining them, were a bit more thorough then the chapters that were dedicated to them in the previous arcs. The Outers development was fine, too and it was very interesting to have some scenes of them alone rather than interacting with the Inners or Usagi, thus portraying them a bit more thoroughly, too. Also, visually the arc was better, since it conveyed the vibe and feeling of it and some scenes were even portrayed in a dreamlike, illusionary manner. And the artwork had become very good at that arc, especially the colors and backgrounds were picked well. The villains were a bit more interesting too, with Nehellenia's backstory and stuff. So overall, it was a pretty charming arc, but it won't be so easy for me to like the manga cause of that. Actually, maybe I shouldn't have said that, liking the manga will be favorable sometime... 

Definitely Infinity!   We get ALL 9 Scouts!!!!  YAY!!!!

I like the dream arc. I am not a fan of in-depth commentary on why I like it, though. I will say that its a pretty intense arc! And the Eternal Sailor Moon form at the end was nice too.

I did like the Dream arc. It seemed like there was a lot of action and drama going on without needing to use too much time introducing new allies.

Dream arc is my favorite, hands down. It's the first arc of the manga that I read I have a habit of reading things out of order and got hooked on it immediately.

Infinity Arc, followed by Stars

dark kingdom and dream! in the manga ive always thought that the telling of the dark kingdom arc is the most superior version of it, i just feel like it had such mystery and had a great ominous feel to it.
and i was never a fan of the dream arc when i was younger and prior to reading the manga but now i feel like it has such a great style to it and is over all (not my favorite) the best story.
but i mean every arc of sailor moon is fantastic in my book

:000 I can't believe I never posted here!

I definitely go back and forth on this question A LOT buuuuut after the recent re-reading with the SM Manga Club, I think I have to say that Dream is my favorite arc du jour!
The fairy tale tie-ins with the amazingly beautiful and regal ending scene...

The whole overlaying commentary on entertainment distractions causing neglect of daily life (which is totally applicable today even without the forces of evil at work)...

The Sailor Quartet reveal...

DID I MENTION SAILOR SATURN'S AMAZING AND MYSTERIOUS CHILDHOOD?? Everything with the Outers in that arc actually is somehow improved compared to Infinity imo. I mean, don't get me wrong... The drama of Infinity was A++++ and it's a very close second favorite for me atm, but Dream felt really well resolved and seeing everyone able to work together again after parting ways at the end of Infinity is just T^T!!

But I totally dig everyone's reasons for their choices too. It's just so hard to choose and like I said, I really do have a favorite "du jour" instead of one that is everlasting in my heart haha. The manga is my favorite rendition of Sailor Moon, after all~~~.

Stars was a perfect and epic as hell finale featuring my all-time favorite villain so it's easily my favorite arc.

I read the manga fairly quickly, and I think the Infinity arc was my favorite. It's just in the middle and I feel it is the part that is already far enough into the story that it's pretty well developed, but also not as repetitive as the story gets sometimes. Also, it introduces (more of) the Outers!