Here's how I see it -
I have seen a lot of threads about those Tri-Hones. Some guys say they work, others say they don't. The only FIRST HAND accounts I have ever read are from guys who describe them like JeffR. I can't recall any of the guys who I know by reputation saying anything about them one way or the other.
In short, to me it's a gamble.
What I do know is the popular synthetics are tried and true. The Tri-Hone may be $30 while a good set of synethetics will be about $110 for 1k, 3/4/5k and 8k, but I'd rather buy the right stuff the first time. The only exception (for me, at least) would be if you are seriously interested in stones AND have the time, experience, and other equipment to make comparisons.