Just recently, I was able to test drive the Linde Werdelin The One Hard Black II DLC timepiece, including The Rock instrument. I shared my experience and thoughts about this watch and instrument on the Linde Werdelin forum over at Watchuseek.
Although I think you just should click the link and go read the article, I can tell you in advance that I really love this timepiece. Stealth looking when dressed casual, and very notable when suited up. The watch feels remarkably light (although it is stainless steel, not titanium) and has the same comfy dimensions as my Linde Werdelin 3-Timer (review here). The Rock is an instrument I have no personal use for at the moment, but it was nice to have a go with it. Feels rock solid (no pun intended) and is easy to navigate.