If anyone's actually interested, I think it's generally a pretty decent show. The original anime suffered pretty seriously from pacing problems; it took soooo looooong to do anything and all the filler led to weird plotholes and pacing. And of course the infamous reused animation was painful because it'd take up like a quarter of the episode with the EXACT! SAME! transformation or attack footage you've seen fifty times before.
Crystal does away with a lot of these problems by ruthlessly cutting out the filler and severely limiting reused animation in the first two seasons--while transformation sequences use the same animation, they cut down how frequently these scenes occurred (in the original anime, it seemed like nobody could ever transform off-screen, but in Crystal, it happens all the time), and the attacks generally don't use reused footage. All of this really helped the pacing, and made fights actually exciting and fast-paced. The third season unfortunately had a lot more stock footage (could Moon Spiral Heart Attack take any longer) and in consequence the fights weren't as interesting. One thing that helped here was the music. In the original anime, the music for each transformation/attack sequence never varied, which led to a weird disconnect where exciting or tense music would suddenly cut out for the same ol' music you've heard fifty times before that doesn't fit the scene. In Crystal, even if the footage was reused, the music generally was not, which helped tie the footage back to the rest of the episode.
The visual design was kind of a mixed bag. Everyone has noodle arms, which is never more obvious than during the transformation sequences when they all flail around bonelessly. It's weird and occasionally creepy. On the other hand, the animation was pretty slick; things actually had backgrounds unlike the original anime where all the fights took place against contextless swirly colored backgrounds (to make it easier to reuse the footage later). And especially in the third season, I actually grew to like the art style. Music and sound design generally seemed pretty good. Can't comment on voice acting--I was watching the sub--but what was up with the translator for Season 3?? Seasons 1 and 2 had perfectly fine translations, they were natural-sounding with few flaws, but Season 3 had all kinds of misspellings, slightly wrong words (no, Sailor Moon is not being aroused, she's being awakened), and ungrammatical phrasing. It was all still comprehensible, but your audience shouldn't be googling "halation" and "domically" to find out if they're actual English words. (yes, both of them are. no, neither of them is something a teenager would use in casual conversation. no, not even Ami)
OK, so... how about the actual story? Crystal is based pretty closely on the manga, which I'm in the middle of reading at the moment, hence why there's little filler. But I can't help but think that you miss out on a lot of the fun interpersonal stuff from the original anime, and don't get the same sense of the girls' personalities. For one example, Rei seriously creeped me out with how nice she was to Usagi... the two of them always had a more antagonistic friendship in the original anime. I wondered if this was just how the manga was, and if all that had been made up for the original anime, but nope, in the manga Rei and Usagi argue a bunch as well. The Inner senshi just all felt a bit generic. Oooh, Ami's the smart one. Rei's the psychic one. Makoto likes plants and cooking. Minako is uh... we'll get back to you on that one. (the poor girl's exceptionally generic in Crystal) The only people who had actual personalities were Usagi, Mamoru, Chibiusa, and... Hotaru, I guess? And none of the villains have much personality at all; they're very interchangeable. That's a definite advantage the original anime has over Crystal, in my opinion--way more characterization of the villains.
Overall, I thoroughly enjoyed Crystal. It sure was a lot easier to watch and less repetitive than the original anime, and felt less "childish". I just kinda wish there'd been more character-related stuff. (plus--maybe this is verboten--but I really love the ending of the first arc in the original anime, even if it didn't follow the manga at all. It's so dramatic and sad!) I wouldn't say it replaces the original anime, but it's probably easier for a newcomer to swallow.
Random other thoughts on the original anime vs. Crystal:
- I wanted to stick Chibiusa's head in a blender in the original anime, but I actually like and am sympathetic to her in Crystal. Good job.
- Tuxedo Mask is still useless, but in the original anime he was somehow still treated as if he was useful, whereas here his uselessness is acknowledged and everyone's aware his only value is to give Usagi pep talks and babysit Chibiusa. So that's nice.
- I'm super glad they used the manga age for Mamoru because while it's kind of weird for a 17-year-old to date a 14-year-old, it's really weird for a 19-year-old to date a 14-year-old (which is his age in the original anime, God knows why)
- wow Usagi is really, really bi