I don't know exactly what the "controversy" is but it's definitely one of the most iconic series and it's been deemed as the mother of all magical girl animes. I couldn't go through it till the end after a number of episodes watched tbh. IMO, the mangá is better and I don't know if it's because I find the fillers in the animê to be incredibly stupid (and there's a FREAKING LOT of them) and so are some of its changes from the mangá but generally, the entire series (both the animê and the manga) didn't work out for me. If you're critical about the main characters like myself, then I don't recommend this animê to you. I just can't stand Sailor Moon/Usagi and her foolishness and she's the main reason why I stopped watching.
So anyway, I'm in the mood to let off some steam so I'll just add/elaborate the things that I can't stand about the series [**SPOILERS AHEAD**]:
- Usagi is a royal idiot, a crybaby, and she's useless.
- She's so useless that every time she faces an enemy, she can't defeat them alone even though the ridiculousness of the enemy's power makes it rather evident that it's weak but she still needs help from the Sailor Soldiers.
- She's a lovesick fool. She even got jealous over Mamoru caring a lot about Chibi-Usa (well, a lot mais than her from what she thinks at least) even after knowing that Chibi-Usa is her and Mamoru's child in the future.
- With that being said, I don't even know why she's the damn leader. Practically all she's useful for is wave that wand of hers and do some purification crap. Sailor Venus should've been the leader. She's mais reliable and mais mature compared to any of the soldiers.
- (only in the anime) In the period where Mamoru/Tuxedo Mask was distancing himself away from Usagi, he still appears in every single battle even though his presence is COMPLETELY IRRELEVANT to the whole episode. There are even times where he just shows up in the middle of battle, throws a rose, and starts to deliver his usual words speech of encouragement as Tuxedo Mask then just disappears. And I'm sitting here like "What the fuck was that?"
You know, if things got better eventually in the series... well, kudos I guess. I just couldn't urso to watch another episode. But yeah, you won't really know unless you've watched it. I just ranted a bit since at first, I really thought Sailor Moon was gonna be good until I got fed up. (Everything in this answer is obviously an opinion of mine. People might not necessarily agree with it but then again I couldn't care less)
Personally I hate it, there I said it, deal with it. I don't really care at all for the magical girl genre and Sailor Moon is one of the most well known examples of one. I can't get through a single episode without rotflmfao. I think it comes down to how much you like the magical girl genre and romance. But like you said, lot's of controversy cause it's so well known, never hurts to watch the first episode I suppose. I just can't....listening to the theme song... I can't not laugh I just....gah I apologize to all of you who enjoy this, I just can't.
I enjoyed it growing up, and one of my favorito filmes is from Sailor Moon. Like egyptprincess7 says, watch the first episode. If there is a maybe to it, watch a few more. It's one of those you either like or don't anime.