Thanks for the opinions! You all bring up really good points.
Patience, I agree that it's important to pick the color you're drawn to, rather than a color that goes with what you have but maybe you don't like as much. I think if you really really LOVE an item in a color that you don't currently have, if you buy it you will find something to wear it with (at least, that has been my experience).
Nicole, I think this cardigan would be really great on you. It hangs really nicely even when it's not buttoned, and if you only button one or two under your chest, it will create a nice V shape. The sleeves are also true short sleeves, not cap, which works great for me and I think will work for you as well. The sizing is true to size. I have the cardi in a medium (I wear an 8 on top) and it fits really nicely, even when buttoned up--it isn't loose or blousy at all, but the buttons don't stretch or gap, either. You also bring up a good point about how I put outfits together, which I hadn't ever thought about, but I think is spot on. Most of the creativity/interest in my outfits comes from the color and I like bright, interesting and clean color combinations. I think that's why I really wanted to get this cardi in multiple colors--it's kind of like having more crayons in my box.
Tanya and Antje, thanks for the encouragement!
Speaking of buying something in color that you don't have--I also really like the Kelly green one! Now, buying 6 cardigans exactly the same seems crazy (black and white plus 4 colors). I love the bright citron (I'm so hoping that the color comes out close to how it appears online, because then I think it could work with my coloring). I also really like the bright papaya, but I have other coral things (and I have my eye on another coral top I'm planning on buying in the next month). Is this coral overload, even though I love the color and it's good on me? I don't have anything really green, but I think it would still work nicely with what I already have. Is it too close to the citron (which is greeny-yellow), so I would end up wearing them with the same outfits? I'd like to avoid that, because that is when I start wearing one over another much more often. So far, the colors I have I would wear with almost completely different things in my closet, with only slight overlap. What do you think? Does that make sense, what I just said? I'm not sure.