I love Reaktor 6. I use the player but the sound you can buy and being able to play synthesisers with your computer keyboard is amazing. It also works fantatiscally in Live.
The use of blocks as template for making your own modular synth is really good, endless amounts of sounds to be made from it. Easy to use and quick to learn if you're a beginner. If you don't know how to build your own patch then you can use some of the pre-build patches that are on offer.
the deeper I dig in, the more I enjoy the endless possibilities.... I've taken to running the standalone version on a separate laptop so I can play it with a controller recording the reults as an overdub onto my main machine, often through a miced guitar amp or tube PA.... its most fun whacking keys down and letting all the modules turn your performance into whack.... fun to drive it with a modern analog sequencer via USB into my 'Reaktor' laptop too
I didn't reallyg et into this software until recently... I think I got turned off by the early versins, but after getting the player to try Prism I decided to go ahead and buy version 6 and I am so happy with the purchase