@Lew, I take your comments about the etiology of sibilance and do indeed agree with them. They are also bold comments and hint at a certain set of assumptions and invite me to erect a defense concerning my own abilites to understand, setup and debug a problematic turntable setup. I will spare you justificatory tedium though and just state very clearly that my comments and findings still firmly stand.
Apart from anything else, I am not the only one to have experienced unfixable sibilance issues with 3p 10.5" and 12". Hammertone also have 4 reed tonearms on site I believe but it does not even feature on their top recommended arms for the Puritas. As I said before, the Kuzma is out in front by some margin but then its a very very good arm with extremely good bearings which the Puritas likes, so hardly surprising. Down the cheaper end, Stefano also gets a very good result with the Schick (I have one on order):
http://twogoodears.blogspot.ca/search?q=allnic
None of this is speculation by the way and you may well get a good result with a Reed as it does seem to vary from person to speron (maybe the armboard/turntable is a factor). Note that I am not denouncing the Reed. It's a lovely arm and I use one myself. Just trying to be helpful.
@Suteetat, Thomas does not like Koetsus full stop (SPU Royal N is his cup of tea) and they do not work well in his 10.5 raven arm. AFAIK Jess C feels the same way. As far as I know though, there is no reason not to run with with a more suitable arm on a Raven deck.