TO be honest, none of them. I got ultimate 9 and heavyocity are the ones I use most but technically they aren't NI. Absynth to me is dull, uninspiring and impractical for electro, massive takes too long to program and you can use your DAW to modulate rhythmically in twice the speed, Razor doesn't have anywhere near enough presets to use on anything, FM8 is no different to Absynth..lacking in usable presets, scarbee funk guitar has no bite, Alicia keys has no punch, Battery doesn't work in Pro tools, am I missing anything? Oh yeah, Reaktor, arguably the worst synth Ive ever used, both in terms of sound quality and usability.
Strings are ok, vintage keys ok, Giant piano doesn't sound giant at all but thin, treblely and weak. Id recommend to anyone not buying ultimate and just go for Komplete9 then buying heavyocity aeon instead of damage and evolve, that way you save yourself $200 and you dont get a lot of useless padding you'll never use. Yeah, the solid mix compression series is useful but most daws come with compressors and eqs and if you're gonna master you should be using Ozone anyway.
If you're buying Komplete be prepared to buy patches or spend a lot of time under the hood. If you dig that sort of thing then great. If you just produce music then just get Omnisphere or something or Aeon.