I was surprised at how effortlessly this component worked.
As others have written, it would be nice if 1) there was 2.5 version of the component and 2) it was able to read line breaks in Wordpress as the start and finish of paragraphs. The component also seems to input all tags as categories, which can be very cumbersome to deal with in Joomla. Eventually, I reconverted without importing my categories as I only had three (but tons of tags that I didn't need imported).
I also wondered to myself why the option to import comments is only available with a commercial Joomla comment component (Azrul's JomComment).
Here's what I did to end up with a pristine Joomla 2.5 conversion of my Wordpress blog.
1. I installed Joomla 1.5 and then this component, JConverter, and JomComment for 1.5 (fortunately, I had purchased a copy of this component some time ago).
2. Ran JConverter and imported users, posts, and comments only.
3. Installed JComments and then imported the comments from JomComments to JComments.
4. Uninstalled JConverter and JomComments.
5. Installed com_Jupgrade2.5.2 and converted the database from 1.5 to 2.5.2.
6. Installed version 2.5 of JComments and checked to see that the comments were still there (they were).
7. Copied all custom HTML from Wordpress to my Joomla template.css file.
8. You will need to copy and overwrite all articles from Wordpress into Joomla in order to redefine paragraphs UNLESS you have hard-coded HTML into your Wordpress articles (I had actually done so out of force of habit with many articles).
The process is cumbersome but, after two to three hours, I ended up with pristine Joomla 2.5 version of my former Wordpress blog. Not bad.
This component needs some tweaking and further development but when you consider that it's free and basically does what it says, that's a lot more than I can say for even some of the most expensive components on the market today.
Kudos and thanks to the developer.