I didn't get good results cause i'm a noob and made terrible mistakes such as light leaks during flowering, got up in the defoliation thing (during flowering also),no perlite in the soil, so i don't think it was the blackstar,I think it did a hella of a job during veg, many tight nodes and no stretching at all, i lsted and made a beautiful bush,unfortunately i screwed up in flowering.. That's why i believe that with another ufo and improving my skills will have a descent yield,not sure about what kind of light though.