The first thing you will notice is that the interface in FruityLoops 3 is completely rebuilt. The Step Sequencer is now a separate window that can be freely resized (no more separate skins for 32 and 64 notes!). The sample browser (now just called Browser) is also a separate window. You can dock it to the left or right side of the screen. The main control deck functionality, as well as many options that were only visible when you open the settings windows, are now easily accessed though the new FruityLoops' panels.
The new Piano Roll view allows you unprecedented power when creating complex melodies - creating polyphonic patterns and slides is easier than ever.
Effects system in FruityLoops has changed a lot too. Now you have 16 FX tracks instead of 8 (with up to 8 effects each). Four FX send tracks were also added, so you can distribute "weighted" effects in the other tracks. The new Smart Disable option disables the plugins when there are not used during the song, thus lowering the CPU usage of your projects.
MIDI support has been removed from the Sampler. But now FruityLoops comes with the MIDI out generator, which has much more advanced MIDI support than his predecessor.
Events in FruityLoops are pattern based now. This means there is no more one global automation track, as in FruityLoops 2.x - events are saved locally to each pattern. Older FruityLoops 2.x projects are imported by creating one additional pattern called "Main Automation" which replaces the global events tracks from FruityLoops 2.x.
More controls can be automated in FruityLoops 3 - the mute/unmute switch and the FX selector in Main Channel Settings are now automatable too.
DrumSynth's renderer has been updated. You can now edit some DrumSynth preset properties directly in FruityLoops (see Miscellaneous Channel Settings).