I've spent the last couple of days buzzing over the sheer depth & complexity of this fascinating sample-based synth,by listening through all of the audio demos & video tutorials and yet,it has the most elementary layout I have ever seen!
The lushness & ultra high fidelity seems to match that of Omnisphere and yet,it's CPU efficient and very reasonably priced!
At this point in time,I have not done a comparison of the sizes in terms of gigabytes between the two(as I am certain that for $479,Omnisphere is quite sizable),but the base price for Alchemy is $249,so it has the advantage of adding additional sounds,as you can afford them.
http://www.camelaudio.com/Alchemy.php-Thom