If you go to the fxpansion site, go to the BFD3 overview page, then go to the FAQ tab and under, "is there a demo" you'll see two links (for mac and windows) where you can download a demo version of BFD3.
I did post a link but the idiot filter keeps blocking them and I really can't be arsed to have to ask the mods every time I want to post a link.
Naturally the demo is limited with less velocity layers and articulations but it still should give you a good idea of what it can do and what you can do with it. There are also lots of user videos and tutorials on youtube which are mostly very useful.
Cheers
Steve