Resco has finally released Resco Backup for Pocket PC. As a long-time advocate of RescoBackup for Palm, this is very exciting news. IMO, RescoBackup is far and away the best backup solution for Palm OS. I haven't really tested it the new PPC version thoroughly, but after a quick once-over and some trial, it seems to include pretty much all the same features of the Palm version.
The biggest advantage of RescoBackup over the other backup solutions for WM is the ability to create profiles (Projects) and flexible schedules for each, whereas the others AFAIK don't have this flexibility, with the possible exception of Spb.
Previously I was using SpriteBackup, which is a great solution. I have never tried SpbBackup, but it actually also looks more versatile than Sprite. As a die-hard RescoBackup for Palm user, I'm definitely going to give this a shot.