or because I trust Waitrose. Bought some Waitrose essential washing liquid and in fact some frozen meat, which I wouldnt do with Tesco. Perhaps it is Tesco's fault with the name. I was substituted Asda Value Chicken, and with trepidation used it it was fine but it would not be my first choice.
Before I discovered LIDL (and cut my shopping bill by a third) I used to buy lots of tesco value stuff. Some things were really surprising...tesco value dishwasher tabs are £1.30 and do exactly the same as Finish which are 4 times the price. The washing up liquid (about 30p) the same. Lots of food bits such as tinned tomatoes, tinned tuna - all the same.
I wouldn't buy value meat, yoghurt or bread though. The meat is full of added water and dextrose, bleughh.
I don't use Waitrose much, (am a Lidl girl) but I use their carpark when I get my haircut and you get free parking if you spend £5! So, I have in the past bought their essential frozen green beans which were tough and stringy and their essential raisins which were full of stalks. The Lidl ones would have been cheaper than even "essential" Waitrose ones and are far superior quality IMO.
As always,you either have to have enough time/Â£ to comparison shop or know what your own minimum requirements are from a product. FWIW I have found waitrose essential toilet rolls to be better than andrex, but it's only my opinion. For foods, I look for the minimum no. of ingredients and real ones as opposed to chemicals. I have been very pleasantly surprised by some products from Lidl, but if I only had time for one shop, it would be waitrose and essential all the way unless it proved to be awful. It does come down to trusting them as a default, for me.