Oh, Twilight and Harry Potter. Two genres that should never be compared, constantly are.
Before I start this post, I've watched all of their movies, and read all of their books. I was paid $500 to read the Twilights, and I started reading Harry Potter when my second or third grade English teacher started reading the first book in story time.
So, let's start with plot. Twilight centers around a teenaged girl that falls madly in love with a 107 year old vampire. The series is centered around their love, and how people from both of their worlds try to tear them apart. Honestly, that sounds a lot like Romeo and Juliet to me (which I personally enjoyed a lot more). Harry Potter's plot is about a boy that survived a curse from the most evil wizard to exist, and his ultimate quest to destroy said evil wizard with help from a range of characters (his best friends, their families, and many others who pledged their lives to helping defeat the wizard).
Let's focus on the female characters. The main female character in Twilight, Bella Swan, seems to be like an average chick. Not particularly attractive, not particularly interesting. She does, however, seem to be inexplicably attractive to Eric (a random geek that talked to her on the first day, that she then treated like shit), Mike (a jock that her "friend" had a huge crush on), Jacob Black (who turns out to be a werewolf, and falls in love with her newborn baby girl) and of course, Edward Cullen (only because of how she smelled, and that he couldn't read her mind). After Edward doesn't show up for a while, and then returns to classes, she starts to almost obsess about him. Jacob tells her of a legend that his people know, and Bella proceeds to research vampires. Edward then confronts her, in the middle of the woods alone, and then they both share that they secretly love each other. For the next three novels, almost every paragraph somehow refers to how amazingly perfect Edward is, and when he dumps her at the beginning of New Moon, she is in a catatonic state for three months. Eventually getting married to Edward and dying in the process of giving birth to their child, Bella is reborn as a vampire and helps resolve a conflict between the Vultori and Edward's adoptive family.
Hermione Granger, the main female character of Harry Potter, is described originally as being mousy, bossy, and extremely intelligent. From her introduction, it was only after Harry and Ron had saved her from a troll that she became their friend, helping them intensely when they needed anything from rule breaking to their homework. Third year, where the awkward stage of teenagers just starting to realize the opposite sex is attractive, brings about all sorts of conflicts between Harry, Ron and Hermione. Hermione's pet cat, Crookshanks, attacks and "kills" Ron's pet rat, Scabbers, only to be later found out that Scabbers was a wizard in disguise and Crookshanks had known all along, being part kneazle. Their friendships all stay the same, even through the trying times. Hermione and Ron seem to awkwardly fall into a sort of love-hate relationship, and it breaks Hermione's heart when Ron starts dating Lavender Brown, after she had helped him become Gryffindor's Keeper. Previously agreeing to go with Hermione to the Slug Club's Christmas party (a club created by Horace Slughorn, professor of potions for their sixth year), Hermione takes the guy she believes would have pissed Ron off the most, Cormac McLaggen (it doesn't work too well). Pretty soon, Ron's and Lavender's relationship fails, to Hermione's and Ron's delight. Seventh year, after seven years of friendship, fighting side by side to help Harry defeat Lord Voldemort, Ron and Hermione share their first kiss after killing a Horcrux. In the epilogue, it is revealed that they had gotten married, and have two magical children.
Yup, huge post, but I personally think that Harry Potter is written much better than Twilight, and gives a better image for girls of all ages to look up to. Twilight concerns me with how most of the readers are girls and may possibly believe that Edward is a good model for their boyfriends. Harry Potter at least shows girls that being smart and fun are easily achieved, and may even lead to find the love of your life.