I wont try to persuade, however SuperDuper is great. I had trouble with my first backup also. Contacted Shirtpocket and and recd the following reply.
"Sounds like it's not responding right; I'd stop it, power everything, including all peripherals, off. Then, start up again and give it another shot."
My problem was I had the Isight camera attached. SD does not play well with I sight. Afterthe first clone everything is fine with the firewire camera attached. Check out
http://www.shirt-pocket.com/forums/forumdisplay.php?f=6