Kroneborge
I think I need to give this a look. Looks very promising. How does it compare do other do everything synths like Alchemy or Zebra?
That's not a question that can be answered easily. There is some overlap in both cases, but there are things that both Alchemy and Zebra do that most other synths don't. SynthMaster, on the other hand, does a *great* many things, but none of them too far out like Alchemhy's additive/spectral stuff or Zebra's (somewhat incomprehensible) wave shaping. Download the documentation and read through what it says about SynthMaster's oscillators. I think you'll start to see what I mean.
Another attractive aspect of SynthMaster is the add-on sound libraries. There are a number of them that pay homage to historic synth sounds - very good stuff, and not too expensive, especially since they are frequently discounted.