Excellent vintage emulator. Very thick analogue sounds. Good presets, very playable and often with mod and aftertouch settings. Sequencer and effects are awesome. Can't wait for free addition of Repro-5 modeled on the Prophet-5, which should be released soon.
This synth is great as a u-he synth, but it's the first u-he synth that closely emulates one specific hardware. The Repro-1 sounds are vivid and live, similar to the superb sounds of Diva. As an emulation, I could compare it to ImpOSCar or rather Monark, regarding how cool the result is. The Gui is also great, those who owned NI Pro-53 surely agree. I don't know how a real Pro-1 sounds, but this software is kickass. The factory sounds are cool, and if you want even new sounds, you go into deeper to the tweaks page and modify the special settings of the synth. The sequencer page is also powerful, has a dual sequencer like the one in Predator2.
For me Repro-1 is not a CPU killer (I use it on a strong PC) and the ZZZ button force it to use even less cpu. It's monophonic, but no one can force you to use only one at a time.
I have gotten $100 worth out of it in under two weeks. I love it. I love all u-he's stuff, but this has quickly become number one! Plus, basses, arps, leads and even some pads are monophonic by nature, so being monophonic is really not as limiting as you might think. And I imagine you already own oodles of polys, as do I. What you're paying for with this is character, and it has it in bucket loads. And frankly, I actually like being limited to monophonic in a lot of cases. It forces me think in a different way.
And lastly (this should be the kicker for any fence-sitters out there), word on the street is that Repro-5 (a polyphonic synth based on the Prophet 5) will be free for Repro-1 owners.