I recently purchased Boris FX - the basic version, thinking I would just use it to manipulate stills which are larger than Premiere can handle.
I client contacted me to say we used the wrong color trash bags in a video which is nearly complete.
Option A is to re-shoot that scene, which would cost about $1000. Option B was to do a color replace in Boris. In about a half hour I got it looking pretty good - it looks almost seamless, all except a very thin border around the edges, but a little blur hides that.
Now if I could just find a way to use the rain effect...