(MINOR spoiler-ish stuff in this review, read it at your own risk)
This, my friends, is an example of the mahou shoujo (magical girl) genre done right. I thoroughly enjoyed watching Pretear. If you're a fan of anime like Sailor Moon, Cardcaptor Sakura, Tokyo Mew Mew, and so on, I really suggest you watch this one.
The Good Stuff: The storyline is really something you don't see every day. It does have its clichés, but there's a lot of unexpected stuff in there too. I like the villain; how she's not evil just for the sake of being evil. There are a lot of little twists in the story that really caught me off-guard, such as one of the characters moving over to the "dark side." Even though you can probably guess how it will end right from the beginning, it's the journey there that counts- and I'll admit, I was really worried a few times! Rabid bishounen fangirls (and possibly fanboys) rejoice; it has hot hot bishies. Oh yes.
There's lots of random hilarity. A lot of it involves Mayune, the main character's stepsister, and her involuntary (and useless) "henchman," Tanaka, trying to play tricks on Himeno, which usually backfire horribly.
Mushy-love-doveyness is, strangely enough, kept to a minimum. There is some, but it manages to be sweet and not nauseating, and Himeno and Hayate's "romantic" moments often end in some sort of amusing mishap.
Himeno is a pretty awesome character. Even though she's scared and a little confused, she keeps fighting and doesn't back down (though she does go through some moments of angst, which shows she's just human).
Also, the transformation/attack sequences don't take up half an episode. Woo hoo! The Bad Stuff: It's a little cheesy- then again, "magical girl anime" is practically synonomous with "cheesy." It's not unbearably so- not nearly as bad as Sailor Moon can be, I'd say. I mean, the villain is called the Princess of Disaster. Sounds a bit more laughable than menacing.
The monsters in the series, though they don't quite follow the tired "monster of the day" formula, seem like there wasn't much thought put into them. They're not very impressive (although I'd imagine if I were to run into one of them in real life I'd think otherwise). They're icky though, so I guess it works.
The ending is predictable, especially if you know the whole title- it refers to Himeno as "Shirayuki Hime" (Princess Snow White). You'll know right off the bat who Himeno is going to end up in love with. It could have one of two effects on you; a happy-bubbly feeling in your stomach while the end credits roll, or a more nauseated one. I'm a sap, so I got the happy-bubbly one.
Overall, Pretear is definitely worth a look for Mahou Shoujo fans. I suggest Japanese with subtitles if you decided to watch it.