Matriarch : Best synth overall

The Matriarch has amazing sound quality, very flexible features that allow experimentation, has a stereo filter, has a stereo analog echo (that is an instrument in itself). If you're curious about modular synths but want to have a proper, tested-and-true input interface (keyboard), this is possibly your best bet. It is also good for people who are frustrated with the endless possibilities and complexities and incompatibilities of the modular synth world, and want to transition to a system that sounds amazing, is experimental and is consistent and unified. Keep a few modules that you really like and get a Matriarch.

The only con would be the somewhat complicated global settings menu, but you don't need to change things all the time and the manual is very clear about how to make those changes. Furthermore, some of the changes can be performed by MIDI CCs.