My number one go-to synth. It just sounds amazing. I don’t know any other synth that has a similar variety of great sounding presets. No MIDI learn, some parameters are not mapped, but the sounds need little to to tweaking.
It comes with a huge sound library. There is barely no sound Omnisphere is not capable to recreate. You need some time to find the right sound. Multiple pages and a huge number of parameters make programming a little demanding. But version 2.5 supports sound programming via real hardware synthesizers which makes programming so much easier. I have developed a map file generator that allows to turn every standard MIDI controller into a hardware synth supported by Omnisphere using MIDI-OX. Soon, you will be able to download it for free on this page.
The supersaw synth. Low CPU load, great sound, easy and straight-forward to programm, tons of third-party sound sets. A must-have.
Old but gold. Like Sylenth 1, a lot of third-party sound libraries are available. My go-to synth for all kinds of sub basses and high basses. Massive is not the cleanest sounding synth, but in many cases, some dirt is exactly the ingredient that many sounds require. You send your lead sounds through Sausage Fattener, Camel Crush or Decapicator anyway, don’t you?