Hi there.
I’ve always used ChronoSync (from Econ Technologies). I have a WD Passport drive that I backup to another non-WD drive. ChronoSync hasn’t failed me in years. I like the fact that you can schedule syncs and backups by a certain time or even when the drive mounts. It’s a very sophisticated piece of software. I’ve dealt with their Support, too, and it’s top-notch.
I know they have a demo version so you can try it out for a while to see what you think. Here’s their website: http://www.econtechnologies.com/
