Currently I have 6 eurorack filters (mostly from Doepfer) and this is one of my favourite. It's a TB-303 filter clone, but it doesn't sound exactly the same (although I don't have a TB-303 to compare). It sounds very similar though, it has that characteristic 303 sound when resonance is set around middle or higher and it's great for making acid lines. With less resonance it's also useful for any other kind of synth sounds. It's cheaper than most eurorack filters, but it can easily compare with the best. Nice to have 3 CV inputs. Doepfer build quality is also perfect. Would definitely buy again.