Approximately, this is what you could expect from a Sailor nib if you are familiar with Western nibs:
Western Broad -> Sailor Zoom
Western Medium -> Sailor Broad
Western Fine -> Sailor Medium
Western Extra-Fine -> Sailor Fine
The extra-fine size is so thin, it does not have any Western analog. The Zoom is also a unique offering, as it lays down a different line width based on the angle that the nib touches the paper. Writing at an acute angle produces the thickest, wettest line possible, which is thicker than the Sailor broad. Writing at an angle that is perpendicular to the page will yield a line of medium thickness.
The Music nib is not a traditional, three-tined music nib. It does have a thick downstroke that results in the broadest line possible with a Sailor pen, while the horizontal line is a thinner, medium size. Although the original intention of the Music nib is to write music, most writers who opt to own one of these pens seldom use it for that purpose. The shape of the nib instantly gives your handwriting a flair of line variation it did not have previously. The nib performs beautifully upside down as well, laying down a drier, thinner line for more concise writing.
Some comments you may read online about Sailor nibs characterize them as having "feedback" or being "scratchy." Of course, ratings and user reviews should be taken with a grain or two, but there is some truth to be had in those statements. The most accurate description I've heard is that the nibs have pencil-like feedback. So, if you love a nib that glides across the page like glass, then you may want to reconsider investing in a Sailor. Also keep in mind that the feedback is going to be more noticeable with the finer point nib sizes.