In reply to marknoo.

I don't know which one you have tried but if you have not tried myRepono I can recommend this. I am running this on several of my client's sites (Some are >250mb in size) and has proven to be a very reliable backup system for me.
They're offering a free trial (you are given a £5 credit) and then it is on a top up basis
I am having 21 sites there so far and the total monthly cost is less than a tenner