There is now an interactive GUI fetchmail configurator, fetchmailconf. You can specify which SMTP error is recognized as a spam block. Following SMTP 571 response to a From line, fetchmail no longer downloads the bodies of spam messages. Mailserver passwords can be parsed out of your .netrc file. Transaction and error logging may optionally be done via syslog.
Host is auto-probed for a working server if no protocol is specified for the connection.
Delivery via SMTP to the client machine's port 25. This means the retrieved mail automatically goes to the system default MDA as if it were normal sender-initiated SMTP mail. Configurable timeout to detect if server connection is dropped. This means feedback is rapid, bugs get found and fixed rapidly. Strict conformance to relevant RFCs and good debugging options.