Safe-T-Cap frame repair

Ok guys...I'm sure there are a lot of do it yourself and professional body men here (maybe some ladies too) who have tackled some bad rust on our beloved A-Bodies. Any one ever use or know someone that has used the safe-t-cap frame repair parts to repair their cars rusted unibody frame. Thumbs up or thumbs down? Thanks in advance for your advice and comments...there is definitely a wealth of knowledge here for sure!