I'm very old fashioned and tend to use batch files for the main directories I back up using xcopy with a /D switch and run with a scheduled task. And use /EXCLUDE:textfile.txt to exclude directories or things I don't want.

Use it at work for clients who won't dip into their pockets for a proper back up solution

Have you thought of cloud storage which gets cheaper and cheaper (or even free) if you have a reasonably speedy and unlimited internet allowance.