Twilight: Interesting book. I enjoy something that isn't the typical perception of vampires. Say what you will about them sparkling, but at least it's not the same old "they burst into flames" idea. Yes, it is clearly a book written for teenage girls, but that doesn't mean it can't be entertaining to others. My biggest complaint is that after 300+ pages of character development there is suddenly a plot thrown in that is resolved in about 100 pages.
New Moon: Same book as Twilight, just change "Chick falls for a vampire" to "chick falls for a werewolf." The plot is initially the same idea just with a different character. Fortunately Meyer introduces the "real plot" a little earlier than in the previous tome. Like Twilight, she presents a somewhat new take on vampire society, and that's been the real draw for me here.
Eclipse: As if she finally got the memo about how to introduce a story, Meyer actually has a story that's not just characters getting to know each other right off from the beginning. She also delves into werewolf culture a bit. Brings up this idea about what would happen if Juliet had said screw Romeo and went off with Prince instead, which I though was a nice metaphor for the whole love triangle thing she had going on.
Breaking Dawn: The best book in the series. A story told from two points of view. Not one, but two plots going on. Even more unique looks at vampire mythos. Read the sucker in three days.
Of course, there are some faults with the series. Meyer does write with a very simple English style, but hey, so did Rowling for awhile. Twilight was her first book so she can be excused for not have the flow of Adams or King, and she does improve over time. And as a man, the romance scenes sometimes got really tiring. One can only hear about how perfect Edward is so many times.
Ultimately though, I feel that much of the criticism thrown at the series and Meyer herself is grossly unnecessary. Sure, you may not like it and have your complaints, but some of things I've read are just absurd and borderline hateful. Half the time, people haven't even read the series itself and are just mad at all the teenage girls who are making such a fuss about (something that bugs me a bit as well. The stories are good, but not that good).
Really though, I suggest giving them a try.