I have a pair, but I probably won't buy another. I think the fit is a bit tricky since there is elastic at the heel. Even though my shoes are a bit big on me, the elastic can start to dig in after a while. I have the same problem with elasticized slingbacks.
For comfort, I prefer a more structured shoe. They're very flat, and I find a small (10mm or so) heel to be far more comfortable.
I do think the bright colors are cute, but I think you could do much better if you're just looking for a basic black or brown.