This one I would qualify as a sort of "Clash of the $500 Niche Synthesizer Modules"
Soulsby AtmegatronYes, this is one of the better YT clips for this as of now. . .
A unique interface that just might work well combined with an intriguing sound make this one desirable IMHO. There have been other similar synths/sound modules produced before with this 8-bit sound in mind, so what makes this one so different...? Wood panels!!
Seriously though what sets it apart is Soulsby is also releasing future bits of firmware--I can't really call them 'updates' because they completely re-purpose the software. The first of which effectively changes the ATMegatron into a wavetable synth.
The ATMegatron comes in kit form as well if you want to save some money/are into DIY builds. Cyclone TT-303
A 303 clone. That about sums it up....oh, obviously it's been updated with MIDI IN, sorry no DIN-sync. Most notable thing about this one is it's made to look almost exactly like the real thing.