When I first started watching SV, I was firmly in the Clana camp, Clark was so cute, mooning over her! But then, yes, I'll admit, her extreme sweetness and perfection began to grate on my nerves and the main thing that annoyed me about Chloe began to annoy me about Lana: their belief that they "have a right to know" Clark's secret. Why? Honestly, why should he tell you everything about himself? But I didn't really like Lana's dark side either, though she seems happier when she's a bit evil; she has purpose in her life and that makes her happy. I can see why; when she doesn't have a cause, she is just kind of flailing in the breeze, which is boring for her and viewers. When she has nothing to do and Clark isn't romancing her, she's just kind of there.
Which is why I jumped on the Chlark bandwagon. A previous poster pointed out something that I've noted for several seasons: Chloe has the qualities that have made Lois Lane a beloved character throughout the years: the brilliant journalistic passion, the element of pushing Clark to better himself, the bf role and (not necessarily currently, but possibly) the love factor.
Lois on the other hand is just this off-the-wall bluster ball. She almost seems like the most one dimensional female character on the show. She's the hot girl who's used to be a tomboy and is all about proving she's the best. Half the time, I feel like her comments to Clark should be followed by "so there! Aren't I so just cute and witty?"
Also, I don't see why people believe Lana and Lois have all the looks on the show locked up. Lana has a classic-type beauty, Lois has a college type of beauty, and Chloe has a clean beauty underscored by that childlike smile that makes everyone misclassify her as simply cute. They're all beautiful women, just in different ways.