[Geekcop]

I can only give you my experience w/ SPB. I've been using it about as long as I've had my PPC (~18 months) and have never had a problem with it. I suspect it works much as the other two do, by creating an .exe of all of your device settings, apps, contacts, pix, etc and storing it on your SD card. One of the interesting features of SPB is the ROM Upgrade mode. This allows you to restore your device when you flash a new ROM, with the exception of settings unique to your previous ROM version. Useful if you plan on doing any ROM flashing.

Whatever product you decide on, it's important you use it regularly. I have mine set to do a complete backup of my device every Monday @ 7AM. The time to find out you don't have an up to date back up is NOT when you've just flashed the latest and greatest ROM for your device and obliterated your 200+ contacts, email settings, etc