I think it would have been 5 had I liked the ending more. I LOVED the premise, and I loved Beth and Jennifer. Lincoln was okay - I think my problem with him was the atypical male-ness of him, although I hate that I said that considering how I've been trying to fight gender stereotypes. But it does seem like every book I read with a male protagonist ends up being about a guy who's super sensitive and has trouble getting over past relationships and blahdeeblahdeeblah.
BUT I still loved this book. I loved that it was late 1990's, and I love how Rowell writes these books in these fantastic and unique settings and then gets to describe the characters in these wonderful 90's outfits and dealing with the crazies appropaching Y2K.
I HIGHLY recommend this adorable book.