Looking at it some more, that's one of the best engineered "cheap" SMPSUs I've seen. Plenty of input filtering, very well spaced out, conformal coated ( good where you have dusty airflow), additional LC filters on the outputs, multiple series resistors for high voltage drops.
Apart from the coating over the sparkgaps, though the coating is probably more of a plus than the less effective gaps are a negative- you rarely see them, or MOVs in PSUs at all.
Seems unlikely they'd have done all that then spoilt it with crappy caps.