I'd like to make a suggestion. The Clean Migration option, which is set to default YES, should have a warning pop up added to it.
I just had all the K2 content on my website wiped out during the migration.
There is some info to the right on the Configuration options, but it doesn't spell out that it's your JOOMLA content that will be deleted. I was expecting the WP data to be removed from my database.
It's WAY too easy to wipe out all of the old content without realising.
Thankfully this was on a development site that was backed up - I'm not THAT silly :P
So to recap:
[li]DON'T make Clean migration YES the default option[/li]
[li]When Clean Migration YES is selected, a pop-up warns you that you're about to delete your Joomla content[/li]
I think this might save someone who might be working on a production site. Hope this helps.