Very good clone of the Arp with the addition of some very good effects, a very versatile sequencer, and an arpeggiater, none of which were available on the original from the 70's. The keyboard is not very good...Behringer states it is a semi-weighted keyboard, but it really isn't. It's a simple plastic, spring keyboard with very little resistance. As it is/was a performance instrument, that's an issue. I hate the keyboard and told Behringer they need to stop advertising that it's semi-weighted. The oscillators are good, perhaps typical Arp, but the filters seem shallow. A problem exists with the HPF, also noted by other reviewers, with a relatively large notch that's missing in the upper register. You'll hear a definite gap . And mine is very scratchy - and a judicious use of contact spray did not resolve the problem...There's a lot of noise from the fader in the upper regions, which, once again, limits performance applications. But, as a sound module, it is capable of creating some wicked sounds, and in many ways much more versatile than the Mini Moog that it challenged back in the day. It had/has sample and hold, and a ring modulator, neither of which the Model D had, which gives it more sound creating advantages. The Arps have a unique sound, totally different from the Moogs, and if that is what you're looking for, then this might be the thing. I have to say, for the money, it's a pretty amazing instrument. They have changed a lot very quickly. I got one with the multi-colorered LEDs, that mirror the colored fader tips of the original. I have heard that the older, late summer 2019 units, with only white LEDs are still shipping. But again, despite some of my negative observations, it's a pretty interesting piece of kit for sound design and experimentation. It will keep you busy for hours if not days and weeks...