I buy a fair number of value products. Everyday Value flour, tinned tomatoes, tomato puree, pasta, spaghetti, teabags, jaffa cakes, chocolate digestive bars (for packed lunches), value bananas, value tinned kidney beans, value rice, value cartons of apple juice or orange juice. I also buy value washing powder, or one of the other discount brands now availabIle. No problem. Value yogurts and chocolate mousses too. Also, I find that there is little wrong with value garlic bread.
I found value part-baked baguettes in our Tesco recently, and very nice they were too. As good as any other.
I used to buy value dishwasher tablets and had no problem with them, but our local Tesco has stopped stocking them.
At the moment we have little choice other than Tesco round here, but an Aldi is planned to open in about 18 months. I can't wait.
Amongst the few items that I don't buy in the value range are meat (I usually prefer it from the local butcher), and eggs (prefer free range for taste and ethical reasons).
I do check out what the offers are each week and work out whether or not it would be economical for us, and do sometimes end up with branded products that way.
In general though, I see most branded products as much the same thing in a more colourful and eye-catching packet, and a correspondingly higher price.
You do have to look a bit harder to find the value/basics/essentials range in many supermarkets. They do so often make sure that what you see at eye level is the most expensive stuff, and there's a reason why they do that.