First, a little history. My father created electronic music back in the day when it was done by cutting up magnetic tapes. He graduated to synthesizers, and built several modular systems. (He also salvaged keyboards, such as an Arp Odyssey which was bent to that only one key played. He took it out of the case, installed a bunch of patch points, added a divider, and sold it to a local college.) I spent a lot of time on my father's synths.
I built a PAiA Stringz'n'Thingz and mixer, but my first synth was a DX-7. Now I've got a Korg Kronos, but I'm getting that modular itch. Being relatively cheap, I don't want to recreate Keith Emerson's rig. I'm thinking more about sticking my foot in the water, but not in a way that limits me in the long run. As such, I looked at the EuroRack modules that included a MIDI interface (might as well use the Kronos keyboard, right?) and a Synth Voice.
It looks like the Pittsburgh SV-1, the Moog Mother-32, and SoundMachines Modulör114 will all work for me.
The Modulör114 doesn't have a traditional MIDI port, but the Kronos has both the traditional ports as well as USB ports. On the other hand, it's also larger and more expensive than the other two. The other two look remarkably similar. In terms of cheapness, not only is the Moog cheaper, I don't have to buy a case until I add a second module. But it's only got one audio oscillator.
So, I'm looking for a bit of advice. Which of these three would make a reasonable starting point, but also be usable in a more expanded system? Or do you have some other advice? (I do know which end of a soldering iron to hold, but haven't etched a circuit board in decades.)