I do not completely trust online software for something like personal
finance. What happens if their business model does not work as well as
anticipated? That happened with a popular photo sharing site several years
ago and when they closed thousands lost their photos.
Or what happens if they need to tweak the business model and realize that
they have a gold mine stored in those databases? Just think what Google
Adsense could do if they see you have been purchasing rabbit food.
I will keep mine on my computer using software that can be had in the public
domain and will keep multiple copies.