Firstly: many thanks for your interest in Mixtikl!
The primary advantage of the standalone version is that it allows you to run at any size. And, it doesn't require a DAW to use (Mixtikl generates audio, not MIDI - if you want to generate external MIDI events output from a Noatikl engine, use the Noatikl application instead!). If you're not particularly DAW-focused, you might find this the most convenient version. of Mixtikl Mac users get this direct from the Apple Mac App Store; Windows users need to get it from our online store.
The advantage of the VSTi is that it works under the control of your DAW, so is controlled by your DAW's transport controls and can route the audio output by Mixtikl easily into your other plug-ins, and if your are a keen DAW user then I'd guess that might be your best route. The VSTi is available both for Mac and Windows. If you're a Mac user, you might also consider the AU version, which is the plug-in variant that works with Logic (and Reaper). Both AU and VSTi variants are in the Mac Plug-in bundle that you can purchase from our on-line store.
One of the interesting things for Tim and I is that we learned a long time ago that every single user seems to have different requirements, so we've simply done what we can to give you all a good choice of where and how to use our tools.