New Sonic Arts Freestyle is described as 'Freestyle is an innovative VST host for stage and studio'. There are more than 10 alternatives to New Sonic Arts Freestyle for Windows, Mac, Linux and BSD. The best alternative is Carla, which is both free and Open Source. Other great apps like New Sonic Arts Freestyle are Giada (Free, Open Source), Reaktor (Freemium), Cantabile (Paid) and VSTHost (Free Personal).
Carla is an audio plugin host, with support for many audio drivers and plugin formats. It has some nice features like automation of parameters via MIDI CC (and send output back as MIDI too) and full OSC control.
Native Instruments Reaktor is a virtual, modular synthesis platform. REAKTOR also provides a platform for modular synthesis in the form of Blocks – a range of sound generating and sound shaping modules.
Lite version of inTone 2, a live performance fx processor and virtual instrument host. inTone 2 Solo only limited in track numbers, not functionality. Almost 40 FX plugins, 1 track player, 1 audio track, 1 instrument track, 1 AUX and 1 master chain.