Triskal ... I have both Alchemy and Omnisphere.
Both are like Triton Trinity in that they use high quality samples and synthesis.
Omni is posher-sounding and has really good core samples, and is prob more like the Korg you're thinking of.
Alchemy sample quality imo isn't quite up to Omni quality, but it's still pretty good and can load sfz libraries.
Both have top synth engines.
Both have easy tweak pages - handy if you need to adjust a release time, or other basic tweak.
Both are brilliant right out of the box.
Both companies have been around a long while and can probably be trusted as a long term investment.
Alchemy make you pay for additional sample sets, while Omni keeps giving away more sounds and samples with each release.
Both have free upgrades to date.