One of the main advantages of the extended contact patch of line contact stylii such as Shibata is that they seem to trace parts of the groove which haven't been contacted by other elliptical or conical stylii. That often means that the sound will be better and like playing a brand new record. Certainly, I've found that to be the case with the line contact stylii I own. I have a few very old records which I bought when I was young, in my "pre-hi-fi" days, which have been played on fairly ordinary equipment, which sound old, nosiy and distorted played with elliptical stylii. However, things like my 681EEE-S, 881S or Shure V15 Type V MR still play them as though they are (almost) new records, due to the different stylus shape. I was sceptical :scratch2: when I saw a hi-fi journalist initially suggest it's because the line contact stylii are playing "virgin" parts of the groove, but having heard the amazing difference in sound myself, I now agree.:thmbsp: It's not the case with all records, of course - I've bought some shocking secondhand records that were past redemption, but many records which do sound bad can be played with line contact stylii, and sound much better.
While you may be right that greater contact would increase the chances of contact with dirt, and hence increase noise, that doesn't seem to be the fact. The line contact stylii are still only making contact with the groove walls, even if it is over a larger area, and not actually with the very centre of the grooves, at the base of the V, which is probably where the majority of dirt collects. Mind you, it probably depends how dirty your records are.
I've always been careful to keep mine as clean as possible, by cleaning them regularly, and using plastic covers over records to keep dust out.
While I doubt you'll hear an amazing improvement in sound (I don't), the S stylus is often better for the reason I've outlined above, compared to the elliptical stylus. The main advantage, though, is that it wears less, and wears your records less, due to the extended contact patch. This spreads the tracking weight over a greater area, leading to less pressure per unit of area, and so less wear. As a matter of fact, Stanton used to regularly advertise that fact, complete with elctron microscope photos of record grooves after being played 200 times to demonstrate it, for their stereohedron stylus, back in the late 1970's and 80's. You could see appreciable wear with an ordinary stylus, and virtually no wear with the stereohedron.
While there is no real need to change the stylus you've got now until it's worn, the Shibata stylus, or any other line contact stylus, is a worthwhile improvement.
-Don
