From my personal experience, I think that the best-sounding pair of earbuds out of the 3 is the Sharp MD33.
Good detail, clear and tight bass, and very powerful mids. Nothing is sonically wrong with these earbuds. There is clearly a boost somewhere in the lower midrange, but it is not bad sounding at all. In fact, they sound much better (or more "fun") than other cans because of this little boost. And for their price, it's a bargain.
The Panasonics sound somewhat more "raw". I don't know how to put it, but there's something about the mids that make them sound this way. They sound great on certain Rock songs, especially those with bright, overdriven thrash guitar chords, but unpleasant on other midrange tones. There is not as much detail as the Sharps, and the treble is clearly inferior, but the bass is tight and punchy. Again, for this price, it's a steal.
The Sonys are, in my opinion, overhyped and sound quite terrible. The bass is totally overblown and very muddy. There seems to be a false impression of clarity when you first listen to them, until you notice that you couldn't make out the little details you could on other phones. Some people actually enjoy the "fun" value of these, with their huge boomy bass and heavily coloured sound, but these are definitely not my cup of tea.
If I were to rank these,
Bass:
Sharp > Panasonic > Sony
Mids:
Sharp > Panasonic > Sony
Treble:
Sharp > Panasonic > Sony
Overall Sound Quality:
Sharp > Panasonic > Sony
Value:
Panasonic > Sharp > Sony