My opinion is that Photomatix does create some very un-natural HDR imaging... HDR is meant to produce images that are close to what our eyes perceive, not to make images that make you wonder if it's real or not! That's why I avoid using Photomatix... PS results are more pleasing, although it's a hell lot harder to tone.
To be fair to PhotoMatix this shot
owes most of it's vibrant colour to post-processing in PS with the three 1eV bracketed images combined in PhotoMatix. I'm afraid I can't remember to processing sequence I used in PhotoMatix though. Sorry.