I have a lot of mould problems around my windows in the winter. Even though I tried cleaning around my windows every week or so with bleach or other mould solutions I always ended up having to put new polyfiller around the windows and having to repaint over the mould after applying mould solution paint. I did this about twice a year.
This product has changed all this for me. I leave it on for about 15 minutes and all the mould disappears. It now doesn't re-appear very quickly.
One note of caution though. It seems to change (bath room) paint colour to white.