Why is this better than the Photoshop Merge? I have not compared them recently, but Photoshop always used to be king of the hill on alignment, it just had poorly implemented / explained tone mapping. Does the Phomomatix plug-in have the manual de-ghosting, which I can see would sometimes be an advantage?
For the subjects that I shoot alignment isn't really an issue so I suppose the Photoshop merge may be completely satisfactory in that department. However, I find that it's a lot faster firing off files to the Photomatix plugin than having Photoshop merge the files. Aside from the speed, I've been using Photomatix Pro for a long time, before Photoshop's HDR capabilities were up to par (at least the merge to HDR) and have been extremely happy with the results. I am definitely interested in your findings if you do a more direct comparison. The plugin only has normal or strong deghosting options (or none if you disable it). But my subjects that I use HDR on aren't moving at all and I'm always on a tripod. Let me know what your results are!