Plug in Guru's libraries for O2 are on a plane none of the O2 patches achieve... the Airwave, OMG, and endless others are absolutely priceless, as are Skippie's instructional videos which must totally more than 40 hours by now will blow you away. Every library video will teach you IMPORTANT stuff.
Omnisphere is by far the most significant single piece of kit EVER created.
The Guru's library's for O2, which add samples, effects setups, multis, arps, and so much stuff you've never imagined are just as significant... and take O2 to an entirely NEW level.
Skippy does frequent 25 and up percent off sales... he's very generous. For example, right now he has a
40 percent off holiday/tax sale on 15 of his libraries . As it's Easter, you have to "find" the hidden gems.... Some of the BEST patch developers on Eaarth now work with him. The diversity of sounds/musical types/textures/rhythms/drums/poly mind benders run the gamut of musical styles... NO library is redundant. You wanna sample how far from "base" O2 you can go? Check out Airwave 1 and the recent Airwave 2 libraries... friggin on another planet... at least 4 vids on these two efforts alone.