In a nutshell...they're horrible, probably even more so than the original ipod buds due in part to fit.
They are larger than the ipod buds and therefore don't fit properly in my ears, whereas the ipod buds do. On top of that, they have an annoying shape-the ipod earbuds are smooth and round, while the cerulean xlr's have small 'dips' around the circumference of the driver, that basically poke your ears whenever they're worn.
As for sound quality...they are a complete waste of $15...but I can't really justify this since I could never get them fit to my satisfaction.
What I experienced was tinny treble, a complete lack of mids, boosted midbass, and horrible extension.
I just don't see how, even if they did fit correctly, they could sound much better.
I'd definitely look into the sennheiser mx series or some low-cost IEM's as an alternative!
