I do about 90% of my shopping their. The veg doesn't last very well. Meat is probably similar to Tesco/Asda etc. It's obviously not the same quality as a local butcher, but your getting what you pay for.
Tinned and jar stuff are on par with names brands, their curry sauces, pasta bake sauce, and Thai curry packets are all really good and I think you would do well do notice the difference. You would probably pay about half ? The cost of main brands. Things like 500g of pasta are about 40p for the cheap stuff.
They do sell 'special buy' stuff which is complet random, so they may do garden bits one week, baby stuff the next, kitchen cook wear etc they do loads of kids stuff in these sales and I've got ds a fair few pocket money toys, all of which tend to last well.
They do household bits again all own brands but same quality as what you may get in supermarket. They do good ranges of alcohol as well, again all own brand stuff.
Inevitably you may find some stuff isn't as good as your used to, but it's worth a shot! There a few bits I can't get but I save about £30 per week shopping their, so walking a cross the car park to Tesco to grab a few bits doesn't really cause much of an issue.
Also you don't pack at the till. Shove it in your trolley. People who pack at the tills are not tolerated.