My Opinions
The Best Season
As I have limited access to Sailormoon because of living in North America, I have seen very little of the original product. I do own the R movie subtitled, but that's my sum total of contact with the original Japanese version. However, having the Internet, I am able to find differences between the original and the dub. These overviews are based on a combination of these factors.
Sailormoon, First Season
The first season has the appeal of a villain with a long-carried grudge. Beryl had participated in the destruction of the Moon Kingdom, and was responsible for all the senshi's deaths, which made her very easy to dislike. The generals were some of the smarter enemies, actually attempting some strategy. One of the best parts of the first season was seeing the senshi get their new powers and learn to fight. However, when re-watching, it was frustrating to have to wait for each senshi to appear.
Sailormoon R, the Alien saga
Ail and Ann weren't all that evil. After all, they had been deluded, and were sort of fighting for their own existence. I think they were probably the least evil of all the SM villains. I found the end explanation of the Tree's existence to be rather strange. This season wasn't one of my favorites, although I enjoyed Ail's flute playing.
Sailormoon R, Black Moon saga
Rubeus, Esmeraude, Demando, Safiru and Wiseman were great enemies. Demando was especially captivating. I mean, really, who can resist those shoes? ^-^ Rubeus was one of the evillest villains, as he never redeemed himself in the end and went down in sort of an insane rage. Black Lady was also a great idea, and helped the audience see Chibi-Usa as less of a brat. The first time I watched this I loved learning about Crystal Tokyo and the future bit by bit, and the introduction of Sailor Pluto. This season was easy to watch several times.
Sailormoon S
I've often read reviews that chose this season the best of them all. No doubt about it, the Outer Senshi rock! Haruka and Michiru added a more sophisticated element to the show, and they have the best transformation music ever! Their transformations and attacks are very well-done. My favorite villain would probably be Eudial, though Tomoe himself was pretty cool. The episodes in the Marine Cathedral were riveting. Hotaru is a great character. My only complaint would be that I didn't find the finale very satisfying. It was a bit of an anticlimax when Pharoah 90 came, because the actual fight wasn't shown! This was a good season, though.
Sailormoon Super S
This is often dismissed as a silly season meant for younger viewers, but I really enjoyed it. The enemies are absolutely hilarious! There was a bit too much talk of sweet dreams, but Pegasus was wonderful. Chibi-Usa came off as much less of a brat than in previous seasons, but she still doesn't get a real attack. Moon Gorgeous Meditation was nice, and the S/Super S fuku is probably my favorite. I liked the Super Senshi's new attacks, too, especially Mars Flame Sniper.
Sailormoon Sailorstars
Haven't seen this season yet, so comments are pending.
To Dub or Not to Dub
Ah, the dub question, hotly debated by anime fans everywhere.
Dubbing is a great idea. It allows viewers all over the world to watch anime in their language, giving it a universal appeal that subtitles just don't have. Unfortunately, sometimes dubbing does not work out quite the way it should.
First of all, a good dub should stay as faithful as possible to the original. With Sailor Moon, this has not always happened. Some changes are allowable, such as the removal of body lines from the transformations. It does not change the majority of the content, and probably gives peace of mind to someone out there. However, other changes are just silly. The Sailors are Soldiers, not Scouts. Besides the obvious Girl Scout, Boy Scout analogy, there's just no reason. Also, they say their transformation phrases and attacks in English! Why on earth would someone go to the trouble to change them?
Also, the speeches. Sailor Moon in the Japanese version says the same speech every day. In the dub, her speech is usually full of puns and changes daily. Yes, a little thing, but I think this should stay truth to the original.
And finally, the thing that bothers me the most. All those valley girl phrases they use! "This is so totally not my scene!" "It's freakin me!" etc. Frankly, I don't know anyone who talks that way. I think it...undermines their authority somehow. Also, when the dub is so worried about impressionable young minds seeing things they shouldn't, are they trying to teach them to talk like That?! I pale at the thought.