Buy Store Brand products to save money

A while ago, I pondered on whether to buy store brand products. Store branded products are products bearing the name of the store instead of a regular more well knowned brand. Some examples are those from Giant or Tesco or Carrefour.
Sometimes, in Tesco for example, you may find a few categories of store branded products ranging from Tesco Value to Tesco Fine Foods to organic to luxury lines. I have not seen it here yet, but I’ve seen luxury house brands in foreign supermarkets. The quality is really there and its cheaper than buying the actual brands.
I noticed while shopping at Tesco last week that the manufacturer for a house brand brand of biscuits was actually Hwa Tai the well known biscuit maker! The biscuits were also much cheaper although I’m not sure how it tastes.
I reckon I’d shop for some foods (if I can locate the manufacturer on the pack and find it reputable) but I won’t buy electronics or air purifiers simple because I’d rather pay for something more reputable for them. But I wonder, are there house branded electronics?