Very handy plugin. I built a website for an association, with 300+ members personal details. The data had to be uploaded from a CSV file, and inserted into a custom post type, with custom fields matched up. This plugin did a great job.
I was particularly pleased that it was able to insert data into custom taxonomies, not just post categories. Good to see you'd added that feature.
I'd like to see a facility to do this in reverse and export data from custom post types, fields and taxonomies back into CVS. I'd pay for a plugin that could do that.
Only problem I've experienced was that it appeared to time out on larger amounts of data. It had actually inserted everything, but it was worrying at the time. Suggestion: maybe give a bit more feedback during insertion, or maybe split larger amounts of data into several processes.