Originally Posted by iDoG
Cortini uses his modular system a lot. So if you want to try to replicate some of his stuff in software, then NI Reaktor 6 is your best bet, probably. The user library has a lot of stuff that would enable you to approximate his eurorack set up. As well as ensembles that resemble more traditional subtractive synths that he uses as well. Either way, it's very deep and flexible piece of software that can keep you occupied for years.
Second this. I got it when I bought Komplete, but got sucked into Reaktor big time. Blocks (the modular system) is great. If you can't find it in the library it comes with, some in the user library has probably already made it. Definitely check out the EuroReakt set of Blocks if you get it. If you do eventually want a real modular system, it's still a good option since you can 'patch' it into your hardware and fill in gaps in your own system.
There's a similar thing from Softube, which has involvement from Doepfer and such. But you have to buy any extra modules you want to make. The user library is Reaktor's real power.. there is some really high quality stuff in there.
I've only had it for a couple of months so I've barely scratched the surface. I'm just playing with ensembles I found and it's great. I don't think it's that difficult to get into. Programming your own instruments seems to be a node based system that doesn't look that crazy to wrap your head around.
It's worth it to wait out a sale, or bundling up if you like the other stuff in NI Komplete. I got Komplete during a sale for about what you pay for just Reaktor right now. Komplete is total overkill, half of it you'll never need.. but since they're throwing it in anyway, I'll take it. If I now ever want to get into pristinely reproduced virtual piano playing... I could.