Peach Girl is a high school love triangle (square?) story that probably wouldn't surprise most people. It's enjoyable enough if you like the genre anyway, so I'd suggest it to people who like this sort of thing but I wouldn't say you'd have to rush out to get your hands on it.
I kept on being reminded of Bokura Ga Ita as I watched this. They're similar type stories in a way; especially in the main conflict of the heroine and the two men in her life (and also some plot points, frankly). I think the overall quality of Bokura Ga Ita was better than Peach Girl, but I thought that the heroine in Peach Girl, Momo-chan, was a lot more likeable than Nana (she *reallly* annoyed me in the second half of BGI).
The first thing that comes to mind is that the pacing of the story is a little odd in my opinion. Sometimes it feels like all this time passes by in a blink of an eye and sometimes it's just plain slow. Aside from that, you've got a pretty sweet -- if convoluted -- story about love, indecision, strength and trust. And what it means to be in a relationship with someone else and how and why we choose the people we do. Sometimes things get over the top, but that's more of a character issue (see below).
The art is generally nice. The two men in Momo's life, Touji and Kairi, made me think of Yamato Nadeshiko Shichi Henge -- I think because of the heavily-lashed eyes. It's also slightly reminiscent of YNSH in the frequent use of SD versions of the characters.
Kairi's voiced by Kenichi Suzumura. I LOVE him. All the actors of the main four characters do a good job, but... Suzumura is tops. =) Saeko Chiba also deserves props for doing a good job of making a character who could have been overly mewling and annoying into a likeable person, despite all the tears.
I thought they did a nice job of making the conflict here. You can see where Momo comes from and you can see why Touji and Kairi are both so compelling and appealling to her. I was definitely rooting for one over the other, but that's probably more about my own taste. ;) The character I probably had the most problem with was Sae -- I mean, we're not supposed to like her anyway, but it might have been nice to have a better idea why she was the way she was... especially since she was SO over the top and extreme as a character. I didn't like her AT ALL, which made her hard to watch -- if there was something -- anything -- that made me at least sympathize with her, it would have been more interesting, I think. At the same time, a critical viewer could say that all of the characters are somewhat... shallow and under-developed compared to the very best of the romance/slice-of-life type dramas like Honey & Clover. They just are... and there's not much explanation why outside of Momo.
I liked it, it was okay. I think the parts I liked made up for the parts that I thought were a little lacking overall. I liked Kairi's character and it kept me interested for the most part. If you're looking for a sweet romance and you've worked your way through the great ones already, this is nice. If you're looking for something really fantastic and haven't seen much, I'd go through Honey & Clover, Nodame Cantabile, Nana, Ouran High School Host Club, and Lovely Complex first, at the very least.