Product review (2 stars): It does work though..
I've been using my diffuser for about 10 years now.  Sure enough, when you first fire up the heat, there is some smoke.  It'll pass quickly enough if you actually use it the first time.  On the other hand, if you fire it up, panic when you see the smoke and shut it off, then it will do the same the second time... and so on.  The odor (after the smoke era) is subtle but you're aware of it.  I found after about 4 years the wooden handle got loose due to the wood gradually turning to charcoal.  But it doesn't come off.

Now after all that being said; it works perfectly!  I've been very happy with the performance of this diffuser.  It allows for mild heating of the most delicate sauces without fear of scorching.  And, as it has a handle, you can move it easily as well as perform the TIP below.

Considering the pricepoint, it is quite the deal.

TIP: When using this to continue heating something at a very low simmer, preheat it by firing up one side first, then flip it over and lower the heat.  It will save the 'catch-up' time to keep the simmer.