I apologize for the thread necromancy, but yes, I have found Jaz to be highly reliable. Mind you, the last time I used it was several years ago. It was an external SCSI setup on a PC I used to own. I had it for serveal year, and it never crapped out on me once and saw hours of constant use.

They are based off of HD technology, not floppy. I wouldn't use Zip as my only backup source, but I'd feel safer with Jaz.

That being said though, it depends a lot on what type of Mac you want to use them on. For ubber reliable backups your best bet is either CD-R (which can get expensive if you backup a lot), or an external HD. The later really only makes sense if you're using an IDE external drive via Firewire or USB.

- John