K-2 : really nice synth on its own

Haven't play the original but based on online comparisons there are some minor differences. The filter on K2 seems more tamed when pushed, plus K2 has an extra filter (more smooth) which makes it a bit more diverse. Oscillators, envelopes, LFO seem identical.

K2 comes with no keys, which for me is a good thing since I can use any controller i want and integrates better with more complex systems and euroracks (yes, you still need to convert hz/Oct to V/Oct like the original). Plus you get midi and usb support and an extra 1/4" output on the back.

Build quality is excellent, heavy and sturdy. I would gig it with no concerns at all. Jacks and Pots also feel great with a good amount of resistance.

comparisons aside this is a great sounding synth on its own (cold and gritty). What you get for this price is insane. I consider it an improved version of the original.