I am going to buy some of these modules to control various hardware and software synths. For the software synths, I think the encoders would work best because they can "pick up" the encoder value and the MIDI implementation is more modern. Mainly I will be using software synths from the Arturia V Collection or Cherry Audio.
For hardware synths, I'm not sure if it's better to go with encoders or pots. The synths I would be using it with are Roland JX-8P, Korg DSS-1, Arturia Minibrute 2S, and Novation Peak.
What do you recommend? Right now I'm thinking about getting 3x EN16, because the encoders can also be used as buttons. I can't think of a reason to get the other modules for controlling synths, unless for some reason using pots would be better than encoders. I don't know enough about MIDI implementations, especially on older synths.