I used to own a Saiga MK (the AK-103 civilian version), and oh damn, it was a poor rifle in comparison to the Sako M92S I also have. Accuracy was worse than mediocre (about football-size at 100 metres), and someone at the factory had actually installed the front sight base slightly canted, so that the sight adjustment range was barely enough when the front sight was adjusted to the far end of the adjustment range. I've seen similar in Romanian and Chinese rifles as well, complaints about their poor quality are common in Finland. In comparison, the M92S can put a palm-sized group (without the fingers) at 150 metres with its iron sights with Sako or Lapua ammunition, so under 2 MOA (that's also what's the accuracy objective is for conscripts). The trigger is also a lot better in the Valmet and Sako rifles.
But on the positive side, I had bought the Saiga for 400 euros and sold it for 550 euros, so it wasn't that bad of a deal.
The reason for the Soviet Union to transfer to stamping from milling was the lower cost of stamping and it also being far less labour intensive (as well as requiring less highly trained machinists), than running full manual milling machines on receiver-sized steel billets. Finland tried stamping, but FDF put stricter requirements on the stamped receivers than the Soviet specs (100% interchangeability of internal parts with the milled receivers, and same external shape of receiver) and it turned out that stamping wasn't so much cheaper than milling, and impractical for FDF when accounting their lower accuracy life (the stamped receiver rifles begun to lose their accuracy quicker), so Valmet returned entirely to milling in FDF contracts beginning in 1983.
In addition to the FDF and international commercial market, Valmet and Sako also manufactured receivers as subcontractors to IMI (Sako dealt with the export to Israel, so the government-owned Valmet wouldn't be directly tied to Israeli sales) and sold some exports sales (Indonesia, Qatar, UAE, some other small batches). Valmet even won the Saudi Arabian trials, but the production capacity was lacking (they wanted a contract for 100 000 rifles within 6 months), so the Soviet Union got the contract instead. Similar trials victory was from Colombia, but the Foreign Office blocked the sale (and Colombia bought Galils instead).