This is one of the best CSV importers I've found. I created a couple of new tables for a client and I needed a way to import CSV content into these tables. I tried a number of other components, but they only worked for stock items (posts, pages, comments, etc).
This component does that and more. It will import data into your custom tables and it doesn't so cleanly and easily.
This has saved me hours of coding and it has a clean, simple interface that will not overburden my clients with jargon.
If you're looking to import CSV files regularly or just to populate data from the get go, this is the one you're looking for.