I tried the registry fix many months ago (probably when this thread was created) and i suspect any improvement i felt was merely placebo. I have also been using Wowtunnels for the past few weeks and during peak times my latency sits at 250-320, usually green. For perspective, normally i would have been 450-700, with the bar being red as often as it would be yellow.
However i refuse to vouch for the awesomeness of Wowtunnels because doing so might decrease the quality of service i receive from it due to the increase in people using it.
The guy running it has been adding more tunnels at a fairly steady pace though (matching demand where required). I just hope donations can keep up with the increased traffic which is inevitable as more people hear about it. The mere existence of the service is contingent upon donations. On a side note, my new ISP at one point offered its own similar tunneling service, but for whatever reason they bailed on it.
If there IS a risk (like account security and being hacked or whatever) i can't be sure, and quite frankly i don't care because i can now pummel cyclones far more consistently that i ever have been able to do so. Not having to cry about latency is truly a great feeling. Blizzard tech did advise me i should stop using it, deeming it 'not necessary'. I beg to differ on that account. Something tells me none of their GMs or Tech guys are oceanic. Just a hunch.