The CSV importer allows you to use a CSV using comma, tab or space separated values. This is handy when making CSVs in Excel as you can just copy paste to notepad and save it as a tabbed TSV file.
The import preview function is also really nice.
It didn't work well when importing repeating events. It does import the events but it takes a bit of trial and error. I didn't have many repeating events so it was easier just to do them manually rather than work out the problem.
One improvement request would be to auto-detect the columns names from the header row. It is tedious to manually select the ten or so columns on every import.