Teetime, your post has made me laugh. When Sainsbury opened up in our local town, a lot of people swore they'd stay true to Tesco. That was fine by me. As Stephen Fry says, 'Tesco keeps the riff-raff out of Sainsbury and Sainsbury keeps the riff-raff out of Waitrose' - only he used a stronger word than riff-raff. 
Then Aldi opened up opposite Sainsbury. The Tesco lot were still pushing their way round overcrowded aisles loyally clutching their clubcards, Sainsbury was a haven of peace because everyone was over the road in Aldi and Waitrose??? It's now full of riff-raff getting their free coffee. 
I only go to Sainsbury once a month for things I can't get in Aldi.
What on earth is, 'You get what you pay for' supposed to mean??