It's really two completely different things, except that one's a sequel to the other. The 2003 OVA is a sex parody of Sailor Moon, with a bit of Cutey Honey thrown in. That's all there is to it, really. It's filth.
However the 2006 TV series is a cleaned-up sequel to it (so what's the point?) and a straight magical girl show.
Both incarnations are... okay.
Papillon Rose didn't start out as an anime, an manga or a light novel. It was a joke website, pretending to be advertising a new anime called Lingerie Fighter Papillon Rose. This was a lie. The website's artwork was usually copied from Sailor Moon (but sleazified) and it didn't have an anime in development. Nonetheless this site became popular enough for its prophecy to become self-fulfilling. Other announcements have included a 25-episode internet series (didn't happen) and a new 2014 version of the TV series (didn't happen).
As for the OVA, it's basically Sailor Moon. The characters, artwork and storyline are all the same. Talking cat turns ditzy girl into superhero and helps her fight a female supervillain. Tsubomi is Usagi. Her hairstyle's slightly different and it's coloured pink, not yellow, but her personality and plot role are identical. Seriously, it's hard not to see her as the real Usagi, a few years older and with no more sense. Meanwhile Hikaru (Dandy Lion) is Mamoru (Tuxedo Mask), while Lama is Luna, i.e. a talking magical cat and the adviser to Tsubomi and Hikaru.
Is the OVA entertaining? Well, a bit. I don't know if I'd call it funny, but the filth can be modestly amusing. What's quite cool, I think, is that it fits. Usagi really would be like that. Okay, yes, canonically she's not, but she's always been a happy-go-lucky airhead who acts on every passing whim and is driven by her emotions. (That's truer in the 1990s anime than in the manga and Sailor Moon Crystal, admittedly.) She's got the self-control of a toddler on crack and she's a hopeless romantic who thinks Tuxedo Mask is dreamy. She's an idiot. Left to her own devices, she'd make every possible bad decision. (This is why she's fantastic, obviously.) Anyway, it feels in-character for this Usagi-a-like to:
1. go to a love hotel with a man about ten seconds after meeting him, because he's hot.
2. be working in a bar where the waitresses only wear underwear and rub their boobs on the customers.
You'd just nod your head sagely and say "Usagi". She's a dear girl, but the poster girl for Thinking With Anything Except Her Brain.
There's even faint canonical support for the Lama/Luna bestiality, although not for her crotch-sniffing and panty-stealing or for the condom on her tail. (Tsubomi is Usagi, but Lama definitely isn't Luna.) At one point she performs fellatio on Hikaru. A cat on a human. Ouch. However Sailor Moon's Luna has had a couple of crushes on human men (Kakeru in the S movie and Yaten in Stars).
Tsubomi's nude transformation sequences are anatomically correct, of course. There are comedy boob superwobbles and random buxom toplessness... and all that's just in the title sequence. The supervillain (Sister Biene) has a fellatio whip attack and her minions shoot at Tsubomi with their boobs. Hikaru drives her off by splashing with something that may or may not be cum over her face. Superhero catchphrases are lewd, e.g. Pinky Vibrator, Rose Pinky Viagra and Rose Orgasm Power Erection.
...and that's it. There's not a lot of point to it, except to be rude. I don't mind it, but it's the kind of thing you'd expect from fourteen-year-old schoolboys. After that, though, the TV show is actually trying to be a regular series.
It had a troubled production history, mind you. The TV show was censored, even down to the opening and closing credits. An uncensored version got released on DVD... but this was then cancelled halfway and it seems that eps.4-6 now only exist in their censored TV versions. I still wouldn't call eps.1-3 steamy, though. Tsubomi no longer works in the sex industry and is instead just an ordinary waitress. One of her friends sleeps with married men, but not on-screen. In fairness the show's trying to keep up Papillon Rose traditions. Lama performs cunnilingus on Tsubomi to cure her insomnia, the monster-of-the-week goes for boob gropes and there's a crotch-in-face attack. However the impression one gets is of a straight magical girl show with a couple of mild fetishes. Tsubomi defends her friends, gets angry with villains and takes her fights fairly seriously. (This makes her less Usagi-like, incidentally, and she's now effectively grown up.)
Even the lingerie outfits aren't racy. Everything's safely opaque and the frilly apron makes them more modest. They're unflattering from behind, though.
Anyway, there are now three Papillon superheroes, not counting the dead one. Quite a lot has happened between the OVA and the TV series, which could have improved the show by being dramatised on-screen. When ep.1 starts, our heroines all have amnesia. Meanwhile their enemies are gods. Proper gods who can resurrect the dead and everything, even if they dress like a cross between Queen Cleopatra and a female wrestler.
Again, all this is okay. Not great. I wouldn't recommend it. I managed to make it through, but I won't be watching it again. Often it suffers from being a sequel to stuff we didn't see, although oddly those are some of the better episodes. At least that generally has some dramatic meat. A lot of the time it's just the Papillon Girls fighting a monster-of-the-week. Personally, I'd have been tempted to discard the fairly dull eps.3-4 and instead expand the offscreen material from a flashback at the start of ep.1 into a full episode or two. Getting to know Dahlia would have really helped, for a start. She's their friend. She died. This becomes a big deal towards the end, which to my surprise was quite good.
I don't think this was a successful show. If it had been, they'd have managed to release the DVDs properly, for a start. Even the OVA isn't particularly managing to be funny with its sleaze, while the TV series is ridiculously tame compared with a ton of anime and yet still managed to tie itself in knots over managing to get broadcast. Ep.6 also looks to me as if either the money or enthusiasm had run out, with places where the artwork's got a bit shoddy. This is an eccentric franchise, if not in a particularly interesting way. It's a sincere, fairly earnest (but not very good) magical girl show that started out as a sex parody. It has some mildly unusual wrinkles, though, e.g. a defeated monster-of-the-week will shrink down into a rabbit-sized cartoon thing that follows you around and becomes your pet. By the end, our heroines have a little collection of them.
This mini-franchise isn't without modest plus points, but I don't think it really knows what it's doing. The anime industry has produced sleaze that's laugh-out-loud brilliant. This isn't it.