I just bought a copy of IC (22) to see if it had anything to offer. [This is just like having hardware ‘gear acquisition syndrome’, but much easier on the pocket than buying things made of chips and stuff). Here are some initial comments (but I may well be wrong on all points after such a short check)
1 As far as I can see it only handles diatonic ionian and aeolean modes (called ‘major’ and ‘minor’, and the first mode of the harmonic scale (odd, I would have thought they would have done melodic minor) [Note : Scaler can do any mode e.g. Phrygian Dominant…] This may be restrictive for some (anybody doing Jazz and probably @jamieh and @Bernd ).
2 Here’s the snag. Midi is output on 5 channels, and if you are a Live user you can’t connect with that, even if you use a multi-timbral synth, as I do (Omnisphere). [With the latter it can be used multi-timbrally if you have, say, 5 tracks feeding Midi which are directed to whichever channel in Omnisphere.]
Unfortunately you have the same problem if you use N instances of a mono-timbral VST with Insta Composer.
As Plugin Boutique point out on their web site, you need some form of midi routing to do this and recommend Blue Cat Patchwork, for which they have put up a video. I could use my copy of Bome Translator to do this, but it’s way too hard for a Sunday afternoon, so I coughed up £84 for this (nearly 4 x as much as Insta Composer …) on the (possibly spurious) grounds that it might be generally helpful at some time.
3 It follows that level mixing has to be done in Blue Cat. The size of the controls make Scaler’s look massive 
4 Omnisphere repeatedly crashes Live with this set up so it’s clear there is a problem with that combination somewhere.
5 I’ve concluded that if / when I use it, I will follow a pattern similar to how I use Scaler, namely, to sketch things out in Insta Composer, then drag midi into Live. Since the tracks are then separated by channel, it will then allow me to use Omnisphere multi-timbrally. .
I haven’t really had much time to play around and see what the sequences are that it can produce. At least from my perspective, it’s not in the same application area, and I think for ‘pro’ use (that’s not me) it won’t be a bother to Scaler.
