Alchemy is my go-to synth. Although not as spectral w/ its engine as Iris seems to be, it does granular, synth playback and VA-sounding stuff. In fact it excells at VA sounding thick and, well, analogish. Works well with Rapture and Dimpro if you have those, which are more "cutting" than Alchemy. And they all can use SFZ files, which is nice.
Of course, the best thing about Alchemy is the granular engine, which can accomplish all kinds of sonic mangaling. If you are into any soundscaping, it is a killer feature. IF you just need acoustic replicants, not so useful. But then, you wouldn't be looking at Alchemy/Iris.
Although I haven't used Iris, I can't help but think that Alchemy for $100 more isn't the more flexible and useful synth. Of course, if you only have $150, then it is Iris. And if you have a steady source of musical mad money, buying Iris now saves you $100 that you can apply to Alchemy ASAP.
First world choices - have fun.
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