This is a great filter. Sounds very close to the original (despite having no experience with the original 121), and the functions are well replicated.
I have however two complaints:
First, the trajectory of the filter cutoff fader is imprecise. When you move about 80% percent of the cutoff slider up, it reaches it's maximum open value, and the last 20% of the fader's movement does not really have any effect on the filter opening.
Second, the jacks are a bit wobbly, wich is probably expectable on this budget module.
I recomend though! Sounds great if you are looking for a budget roland-style filter (it has that nice roland timbre resonance).