I second this.
The plugin creates an SQL dump (ca. 35 MB) and leaves it in the backup directory. I suppose it also tries to send it via email, however, due to the file size this mail is never received.
So I noticed several problems:
1) Old dumps are not deleted (sometimes). There are files older than 2010-12-21, so this did happen before 2.2.3, too.
2) Backups are not mailed any more. My last mailed backup was on 2010-11-14. I scheduled a weekly backup.
3) SQL dumps are not compressed any more. Probably since 2.2.3. Maybe this is due to the large size of my dumps (just found http://wordpress.org/support/topic/wp-db-backup-creates-file-but-no-email-is-sent?replies=13 and will check).
PS: Some googling led me to this gem, where they unpack a gzipp'd file in chunks. This should also work the other way round.
I would offer writing a patch for the plugin. Is there only one part where you compress (below "Try to compress to gzip, if available")?