Story
Main character Nina accidentally swallows the 'crystal pearl', an item necessary in order for trainee magicians to pass their test. She comes under attack from various wizard candidates as a result, but fortunately, two of them choose to stay by her side and protect her until the test's time limit is up.
The majority of the series was slapstick comedy – when Nina wasn't arguing and/or falling in love with her guardians Zero and Ichii, the three of them were 'battling' against whichever incompetent duo appeared to try and kidnap her and the pearl that week. It had its moments early on, but got repetitive VERY quickly, and overall felt like it was aimed at a younger audience
We had a beach episode and a hotsprings episode. There was a body-swap episode. The romance was cliché, and went nowhere. It just felt like the show stuck to every overused trope in the book. Nothing sticks out in my mind as remotely original. At least it made sense and ended on a vaguely satisfying note, I guess?
Characters
As with the plot, the main characters were seriously lacking in originality. Zero was your strong, argumentative but nice on the inside guy, while Ichii was friendly, gentlemanly, but slightly mysterious. Bizarrely, they seemed to swap personalities in the flashback episode that looked at how they first met. Nina was the most generic shoujo series lead ever, there's honestly nothing worth commenting on.
The first few side characters were much better – I actually liked San and Forte, their botched attempts at capturing Nina, their master-servant relationship, Forte's reluctant cross-dressing, the lot. The episode that focused on their past was by far the best in the series. Ichii's deceptively young, obnoxious fiancée Rokka was amusing as well, and I didn't mind her partner Gou.
Unfortunately, every other side-character introduced after them were inferior clones, that seemed to get worse and worse with each generation. Did we really need another fiancée, and two more otokonoko characters? Surely the point of introducing new rivals is supposed to be to add variation?
Animation and Sound
The animation seems pretty low-quality for its time, which was 10 years ago. Mostly standard 2D animation, but with a lot of static pans and off-model characters. The fight scenes did not look great, but thankfully they were never the main focus of the series. The CG used for the snake in the first episode was laughably bad, I'm glad they didn't use it again after that (outside of the budget-looking explosion effects).
Character designs were nice for Nina, and most of the side characters; main male duo looked as boring as their personalities.
The most positive thing in this series, for me, was the music. The OP and ED themes, while not the kinds of music I'd listen to outside of the series itself, were cute, catchy, and suited the series well. The insert themes were also fine.
I don't usually comment on voice acting, because 99% of the time it sounds fine to me. In Mamotte! Lollipop, a lot of the characters sounded bored. That didn't help combat my own growing feelings of boredom.
Overall
Generic, repetitive, below-average production values for its time. Hard to justify wasting your time on it 10 years later. But then, I'm not the target audience.