One of my sisters and her daughter are true fans (i.e., fanatics) of the Twilight saga by Stephenie Meyer. On the other hand, one of my teenage nephews said he got bored on the first page.
After hearing so much about the books, my other sister and I decided to read them. She’s read all four, and I just finished the first one. We agreed on our assessment: The books are worth reading once, but we wouldn’t buy them or read them again. (For the record, we have both read a lot of fantasy; we both really enjoyed and have reread The Obsidian Mountain Trilogy by Mercedes Lackey and James Mallory.) I also have no interest in seeing the movie versions.
I guess I have trouble willing suspending my disbelief enough to accept that a 17-year-old narrator could sound so mature (more like a woman in her 20s or 30s) and that a being so old could fall in love with a teenager. Meyer adequately explains his physical attraction to her but not his romantic feelings.
I can understand why teenage girls are so obsessed with the series and teenage boys wouldn’t particularly enjoy it.