I have spent hour trying the other backup components before I found this one. I tried JoomlaConer and JoomlaGhost. Both were difficult and problematic.
JoomlaPack is simple, quick and reliable and best of all FREE!
I have now used it on Joomla 1.0.x and 1.5 sites (the lastest JoomlaPack1.2 release). I have never had a problem and restoring sites is simple.
One of the best components for Joomla and one that every site should have