For me, Reaktor is what makes my day.
It's a synth, it's a physical modeller, it's an effects rack, it's a mastering module, it's a mangler, but wait!
There's more!!
While it will take a lifetime to master and another lifetime to explore the User Library, simple changes like stringing together some synths and effects are easy.
I have had Komplete 5, 6, 7, 9 and 10 and I am a Reaktor, NI effects, Kore, Machine and Kontrol beta tester.
I don't think I would upgrade to Ultimate unless you have the cash.