Similar apps mangle the APN list of your phone, potentially corrupting it.
DCSwitch uses android''s undocumented services to enable/disable the data connection in a clean, mean and concise manner.
NOTE1: HTC SENSE not supported.
NOTE2: Does not work on Gingerbread. See and star this issue to make it work again: http://code.google.com/p/android/issues/detail?id=15031