It's not about the cloning but the quality control. For years Behringer didn't make any synths, just outboard - processing modules like compressors, gates/limiters, feedback managers, effects, small mixers and so on. These were original designs rather than clones of anything. The main attraction was that they were very cheap compared to the competition; sound-wise they were mediocre except for maybe their Composer compressor which was sorta good. The cheap aspect made them quite popular with aspiring musicians, especially electronic ones. Reliability was not too big of an issue because if a Behringer unit in your rack stopped working you could afford to just replace it. But they were absolutely not up to the rigors of commercial use, lacking consistency and reliability.

I like the company in a general way because I'm a big believer in accessibility to technology for entry-level people, and innovating on price is as valid as any other area (and they have innovated in many technical areas since). There are a lot of rent seekers in the pro audio industry and Behringer found a niche in the market where they had no direct competition. After building a solid commercial foundation they rolled the profits back into other areas, from cloning classic synths and guitar pedals to acquiring high quality live sound vendors like Midas. Quality-wise, their products are now really solid.