I found I enjoyed the Manga more than the Anime.
I grew up watching the anime, but feel that I only truly understand it now that I've read the manga, where things are explained a little more in depth.
Sailor Moon
The backstory with Serenity taking her own life due to Endymion's death was soooo much more dramatic and heartbreaking then them both simply getting zapped by Beryl. And their was the beautiful scene where it was going to repeat itself, but both were saved by the pocket watch and the stones they had on them.
Sailor Moon R
I wasn't even aware that the people of the silver millenium had longer lifespans until I got a hold of the comic! The anime is on tv therefore it has to be a little more action packed and flashy, but the manga had a chance to explain it's roots and I LOVE backstory!
Super S
The scenario of the Golden Crystal in Super S being Mamoru's made a little more sense then the anime. I mean, he's Prince of the Earth, why don't he get no bling!?! Seriously though, it gave his character a little more purpose.
SailorStars
The 30th century was shown more in the comic, even getting some screen time in the Sailor Stars arc, where the future was being changed by Sailor Galactia's destruction.
A huge fault with the anime was Sailor Moon/Usagi's english voice actress from Sailormoon S and Super S! It was sooooo terrible and destracting! It sounded like she was 40 yrs old (awkward in the scene where she's asked her age and she responds 15 like some crazy old hag . . .)
There were a few extra tidbits in the manga, such as the Amazoness Quartet becoming Chibi Moon's team of senshi, human forms of all their feline pals were shown and last but not least it had Sailor Cosmos, which I thought was a wonderful end to the series!