I like flame, Paintbox just seems old nowadays. Even if HAL etc. are coming to replace it.
If you ever get a chance to play with one - it's probably one of the most lovely pieces of kit you could ever find, having full real time effects, pushes paintbox out the door.
Although, nowadays many people use combustion, and junior PC version or Adobe After Effects becuase they do virtually the same work, and as high end, but not as fast.
Fire is a high end editing system - you might do programme conforms in it. But Inferno (also made by Discreet) is normally used for short form work - graphic sequences, commercials etc because it offers far more maniplualtion abilities/layering tools than Fire. The are both based around Silicon ONXY computers.
BBC Resources recently spent a fortune buying both a Fire and Inferno - previously only available at top end facility houses in Soho. (and at £600 plus per hour to hire!).
Edit - BTW - Paintbox has been around for years - early 80's. It is used for still images only, and has very very basic animation. Paintbox is comparable to Photoshop, except with Paintbox you are working directly on a tv monitor. Paintboxes are fab to use though.