R. Shlomo Aviner on wearing tekheles (blue) strings on your tallis and tzitzis garments (link):
Q: Should I wear the techelet (blue string) which is available today on my tzitzit?Let me state for the record that R. Hershel Schachter wears tekheles and tells people that Rav Soloveitchik would never have worn it.
A: Almost all of the great Sages of our generation do not agree with this new techelet and our eyes see that they do not wear it on their tzitzit. We should therefore act in the same way, except for a person whose Rabbi tells him to wear it, as we say, "Get yourself a Rabbi."
For a longer article in Hebrew by R. Aviner see here (link - PDF) and two responses here (link 1 - PDF, link 2 - PDF).