I generally only use the high and very high light smoothing settings in Photomatix. There are rare occasions where I'll use the medium setting. The lower two are garbage. They remind of processing HDR in Photoshop CS2.
This image is the result of an elaborate workflow. I combined three images in Photomatix, and genrated an .hdr file. I then opened it with DynamicPhoto HDR (which objected, but loaded it anyway.) I spent quite a bit of time adjusting the tone mapping in DPHDR and saved it as a jpeg. Then I worked it over pretty thoroughly in Photoshop. The end result is kind of bizarre, but not without merit. The effect of using Photomatix for the HDR process instead of DPHDR seems to be a lot less CA, a bit less noise. Likewise, the image was much higher in contrast. I'm not sure if I like that last bit.