Boards mag April 2007 had this to say in it latest review when testing the 2007 Tushingham Rock

"Performance: While not feeling a standout when used on its own, this sail came out as the favourite every time we tested them all head to head. (Against NaishForce, Neilpryde Alpha, North Ice, Gaastra Poison, MaiuSails Legend)Its low end power is good, being of the springy, easy to pump style and holding the leach fairly tight. It can be bagged out in very light winds to provide power rather than change up size. As the wind increases the sail responds well with extra downhaul and outhaul.
We think this is the best rock we have used in several years.

Popularity: Everybody bar one who used all the sails back-to-back on their recommended masts picked the rock as their favourite (and that one person elevated it to favourite when rigged on the Tushingham RDM mast!). It also performs well with most other masts, proving itself to be very non mast critical."

We still have demo sails if you want to try one.
Cheers
2ndwind sailboards

Got to agree with the review, I've tried a lot of sails and the Tushingham Rock "Rocks". The stability and wind range is amazing, hell strong, great value.