Timeouts occur on most servers when importing any type of file not just a CSV. Getting large files to import is a matter of PHP configuration, maximum execution time, maximum memory limit and other settings. WordPress configuration can also affect upload/import performance.
You shouldn’t rate this one star based on your lack of knowledge in server configuration. Try dragging and dropping a few hundred images in to the WordPress media uploader and you’ll run into the same problem, your server timesout chokes and stops uploading.
If you need to remove 3000 posts in one go that’s another topic all together but not very difficult to find a query to do just that.
The plugin works perfectly well, better than paid plugins. How many rows of data you attempt to import is up to you, but don’t expect most shared servers to handle more than a few hundred rows of data with minimal field values.