I've been using Fusion on and off since version 5. However I really became interested in what the program had to offer, when Blackmagic bought it out, and re-released a great deal of the program for free in version 7.
I'm even more pleased to find out they've gone multi-platform in version 8. With Mac OS now supported, and what looks like Linux support to come in the future. A great step forward for a really solid and good value compositing program.
Looking forward to rolling my sleeves up and seeing what can be done with this release!