Has anyone tried the R.O.S.E.?

The Roxanne Optimal Strand Estimator (R.O.S.E.) is supposed to estimate thread count. I haven't purchased one yet, and am wondering if anyone else has tried it. I have only found it online, and so far Colonial Needle seems to have the best price. If you've tried one, please let us know if it works!
http://www.quiltersbuzz.com/2006/02/..._fabric_q.html

for sale at this site also:
http://www.colonialneedle.com/cgi-bi...e_list_roxanne