How is your experience with the DPO of Make Noise, is it worth the investment? I am (extremely) happy with the STO of Make Noise but I wonder (looking at the price) if the DPO can cause me that much pleasure as well?

No doubt! DPO has a very cool, rubbery FM sound. It is also nice to be able to use linear and exponential cross FM modulation at the same time.

That said, I love the Instruō Cš-L too. It has a different sound. More.. rigid, harsh even, but good. It has quite many functions that the DPO lacks, such as ring modulation, fold on both oscillators, more outputs and so on. It is warranted to have both.