Guess all down to cost, cheap components= more profit.

Ironically, the cheap fan inside was replaced with another cheap fan of which is quiet . Maybe luck of the draw as they are very cheap. Other than that(not really a major issue as i put up with it for a year), its been faultless.

I usually or have recommended the opus several times of past, for around $30 its hard to beat imo.

Liking the c4-12, like just being able to place cells in the bays without pressing any buttons. Also the auto charge setting it chooses , seems to be spot on. Other than one of the springs snapping(again cheap components), its been very good so far. I have the c4-12 and 3100 v2.2 sat next to each other for most of my down stairs charging.