Does anyone want to convince me not to get a Microfreak? This would be my first foray into keyboards/synth and I have more interest in making some interesting sounds out of the box than sitting down and learning how to "play piano." The Microfreak seems well suited to this but I know basically nothing about this stuff. (And I don't care to dive into the money pit of Eurorack.)
I had one for while. I'm not much of a keyboard player either but found the controller pretty neat. The arpeggiator is a good one, the mini-sequencer is alright, and I found the Hold button really handy both for drones and arps.
It'll do interesting sounds for sure. There's a good variety of algorithms for the oscillators, including some solid bread and butter stuff that's worth coming back to regularly, some odder but still excellent things, and just a couple that I don't really think fit the instrument very well (many of them came from open-source Mutable Instruments Plaits code and they didn't consult with them about their choices, adjusting control ranges and defaults etc.). The filter sounds pretty great IMHO whether you want snappy plucky sounds, or slow sweeps to pick up different harmonics in a massive chord or cluster.
One downside is you can't directly control the VCA with pressure. The VCA is tied to an envelope. You can assign pressure to modulate the sustain level, but you get still get the attack stage up to full volume and then the decay back down, so at minimum, an unfortunate little click. The pressure also doesn't have any slew to it so it's pretty unstable.
The main reason I wound up selling mine was I mostly found myself using it to take advantage of the controller and arp/sequencer -- the synth itself wasn't offering me much that I can't do just as well or better in modular or software or the Minibrute 2S. And it's not entirely knob-per-function, and the longer I mess with modular, the more insistent I am on that (even though I still like using software synths, go figure).
For what it's worth, I bought mine in September 2020 at a discount for $280, sold it last month for $250, which is still well under Reverb prices...
I don't know the Hydrasynth that well, just messed with one briefly at Knobcon when ASM suddenly appeared out of nowhere with it, and thought it sounded great. AFAIK the Hydrasynth is fully digital but also polyphonic, where the Microfreak is a hybrid but there's just the one analog filter, so it's paraphonic.