Aside from minimizing instability, turning off Turbo Mode also allows you finer control over the overclocking process. May I suggest you look at the link provided in my previous post? It leads to easy-to-follow resources on Overclocking a Core i7.
A blanket statement that turbo increases instability is wrong (how many stating this actually have i7's and can state from experience). Mine was much easier to get stable with the 21x multi both with and without HT. One thing that seems to have some validity is they like the odd multis more than the even, but it seems each setup likes it's own combination.
Here are a couple shots of dome stability testing I have done both with and without HT enabled and all with turbo enabled.
I found your link to be very informative and interesting.
However, I do not think your conclusion is correct. In the article it states that they got better benchmarks with a moderate overclock and turbo mode than with a higher overclock without turbo mode.
Thinking about this, the use of turbo mode should be determined by the number of cores that your application can profitably use. If it is for gaming, where only one or two cores are generally in play, then the higher temporary multiplier would be best. If, your application can utilize all 8 threads, then the higher overclock approach would be better.