-Includes the Halion Sonic plugin and all of its instruments.
-Adds 5.1 versions of the pipe organs, nylon guitar with more articulations, and a few more ethnic instruments.
-270 extra presets, mostly using the Halion Sonic samples to demonstrate the basics of the MegaTrig
-Much, much deeper editing, and workflow optimized for building and editing complex instruments fast.
-FULL access to all synth engines: Sample, Virtual Analog, Granular, Organ, Wavetable, and in the future, FM.
-Much more flexible effects routing. It's possible to build an instrument where every note has its own insert and send effects.
-Advanced sample import and export functionality.
-Very advanced wavetable and sample editors, with automatic loop point detection and slicing.
-More flexible modulation through the use of multiple mono envelopes and LFOs, and MIDI scripting per layer.
-Extremely modular interface. Everything can be docked or undocked, made into a separate window or a tab, and you can save each window or the whole plugin interface as presets.
-Built-in Sample/Preset Library creator, and Macro Page builder with scripting support. You can make libraries for Halion, Halion Sonic and the free Halion Sonic SE.
Halion Sonic 3:
-Editing the stock presets is at about the same level as a hardware module like the JV-1080 or Yamaha Motif.
-Can load extremely complex instruments built with Halion 6, but several parameters can't be edited unless they're exposed by the macro page.
-Full access to the Virtual Analog synth engine. The Granular, Wavetable, and Organ engines are also available, but you're stuck with the editing options made available by their macro pages and quick controls, and you can only use the samples provided by the library's creator.
-Good enough if you only plan to use presets, or only make minor edits.
-Content almost completely different from the Halion Sonic SE included with Cubase.
Halion Sonic SE 3:
-Can load all libraries made for Halion Sonic, unless the library's creator decides to make it exclusive to Halion and Halion Sonic users.
-Can use the Halion synth engines if they're used by the library.
-Editing is limited to only what's made available by the macro page and quick controls. This includes the preset's insert effects and sends.
-You can only add effects to the Master output and the 4 Master sends. To process each instrument individually, you have to use one of the 16 outputs and route them to your DAW.
-The free version comes with no content, it's only a player for libraries made by the users and Steinberg.
-The version that comes with Cubase comes with almost completely different content compared to the full version. Each Cubase "tier" adds more instruments and samples.