These were released some time ago and are now on a discount.
When they were released, I wondered if I want or need, but I didn´t use the original hardware in the past, dunno how it sounded and never missed.
I sometimes used vocoders, Roland SVC-350 rackmount
https://www.vintagesynth.com/roland/vocoder.php and some software, SCOPE devices included, but not much.
Software phasors, graphic- and parametric EQs are out there in masses and some really good ones for free.
P.ex. the FBM Frequency Shifter
https://www.fullbucket.de/music/freqshifter.html IS the Bode device known from MOOG Modulars,- and is a/ the ring modulator and frequency shifter in one device.
In fact, these modules were the most interesting for me and from that bundle.
Leaves the String Filter ...
But do we need in times where we got high quality string emulations as samples and/or devices like Sixstring or similar VST/AU toys using Karplus Strong etc.?
OTOH,- 39 bucks isn´t much and these toys look tempting at least.
But I always ask myself if it´s worth the investment and learning the devices or if they will be just only photo realistic files cluttering my drive w/o much of use.
B.t.w., I use many of the C.A. synths incl. Polymode
https://cherryaudio.com/products/polymode-synthesizer ...
It offers "resonators" which IMO is a derivate from String Filter w/ less bands.
I only bought because I was interested in how a Polymoog worked, same w/ Quadra.
As interesting it is, you also learn how limited the old hardware really was and the so called "magic" seems to be a lot of hype too.
This even they improved the software versions over the hardware already.
Bud