The latest free update from Omnisphere - version 2.5 has added a number of new features, not only do we now get four layers - doubling the amount of synthesis already available. But the new Hardware Synth Profiles are one of the biggest new features.
Essentially they allow you to connect a hardware synth (there are currently 20 supported), the structure of which is replicated in software, and maps each (or most) knob and button directly to it's counterpart in software. It's not just a matter of mapping but a deeper integration with modulation routings and effects being instantiated behind the scenes.
A profile can be loaded per instance of Omnisphere, in our setup we had Ableton Live with four, the additional profile notes offer good instructions on how to set each up to use.
In practice it's a pretty compelling experience, and while you are unlikely to buy synths specifically to use in Omnisphere, if you already own one or more of the supported synths, then it could be just the thing.
Gaz Williams and Nick Batt hook up four of the supported synths and explore.
Omnisphere 2.5 is a free update for 2.0 owners, Or can be purchased for £339.
Supported Synths (as of October 2018)