With Lidl it's not so much that their products are particularly cheaper but that they are better quality for the same prices that you pay at Tesco or Asda.
Luckily I can visit both Asda and Lidl and B&Ms all in one big huge shop as they are all within walking distance.Plus I can get the cheapest petrol in the area from Asda.The only reason I ever visit the new Tesco in town is because it's quieter and it's not far from the local recycling centre and the garage where the East Europeans offer a £5 car wash..
When I want something really special then I pay the extra and go to Waitrose.