Scaler is fantastic in generating MIDI pattern based on User-defined parameters and marrying it with music theory.
In this regard Scaler is similar with Synfire from Cognitone although approaches and implementation are very different.
What lends me more to Scaler is its super-sharp focus (not trying to offer DAW-like functions), a modern yet simple UI, an agile dev-team combined with a active and large community.
Nevertheless Scaler is missing User-defined Phrase-Editing, which limts creativity to some degree (complaining on a high level).
I think the Scaler-dev team might become inspired by the way how Synfire offers User-defined phrase editing.
Here’s video demoing it:
My understing is that phrases are built in Synfire by seperating Harmony from played Notes by a concept they call figure (which does not encode specific pitch values but rather relative pitch and note length), which can be manipulated extremly well. To me its a very compelling user-friendly (intuitive, recyclable) paradigm and seems very powerful.