I've used Photomatix to process multiple exposure images for HDR, and have been generally satisfied with the results. However there are some scenes that I haven't been able to render with the dynamic range that I know is present. Additionally, excessive noise if frequently an unwanted outcome of this processing.
This morning I ran across a different way to process images for HDR, starting in Photoshop to create a 32-bit image, then using LR for all the heavy processing work. I gave it a try with an image a took a couple years ago (sorry, not a nature shot) and am very happy with how it come out. I failed to run any noise reduction before starting the process, so I will go back when I have a little more time and try it again, but there really isn't much noise on it now.
If you want to learn more about this method, watch this YouTube video to get started...https://www.youtube....h?v=xMMngpxz5jA
Here is my first pass at using this method...