MSoundFactory may well be the most powerful instrument out there. It’s modular, so you can have any number of oscillators, filters, samplers etc. you want. It features per-voice and global modulation, full MPE support, the best sounding oscillators on the market, a fully modular effects engine.
A beta version is available for purchase with an introductory price.
MSoundFactory requires content pack or another plugin to work perfectly. See installation notes for details.