Nathan Yau of the excellent Flowing Data blog has written a good review accessible here. Yau writes:
While there are a lot of free options available, none come to mind that work as well as indiemapper, as far as fully customizable maps go. So it's an in between the no-cost and high-cost GIS tools. Info designers who want to include maps in their graphics will probably find indiemapper especially useful. CSV import will also be a huge plus if they can work that in.