I personally haven't invested in a franchise, but a couple of my friends have, for two of them it went phenomenal and they are doing exceptionally well, they have become millionaires in just a few years, the other three went belly-up.
I guess it depends on what the franchise is, you need to do research on what location, who your clientele would be, do some leg work and put together a business plan before you commit to buying any franchise. AND know the business, as a novice in a particular field you may set yourself up for trouble.
Just my 2 cents.
Carola