Funny enough, I get +1 point to Simple rep for each approved niche that I suggested. The value changes several minues after the approval period ends. What will happen if somebody manages to sucessfully suggest more than 100 niches? )
The Quality analysis component is more tricky. At some point in time it boosted from 0 to 5 without any apparent reason and since then remains unchanged.
I went from 3 to 6 in one day just commenting on niche suggestions.