We get what's 'nice' tbh.
I'd rather Walkers crisps vs supermarket as that kind of crisp i find walkers far better and consistent.
Lidl 'mccoys' are nice, but the consistency is bad - some bags taste of nothing, some half the bag taste nothing and the rest has flavour on it, and occasionally, like the bag I've just munched, all of it has flavour and is nice.
Prefer lidl dark chocolate digestives vs other, but that's because lidl do nice dark chocolate imo.
Prefer sainsburys ketchup and decaf tea, their normal tea is good too but I prefer Yorkshire. Not that I can drink it anymore. If asda decaf hasn't changed since the last time we got it - it can **** right off.
De cecco (or barilla) pasta mostly, because supermarket stuff is generally naff with a few exceptions.
Nescafe gold decaf - though I used to like the lavazza instant. I've tried supermarket ones but never to much success. The lidl one wasn't bad but I do prefer the brands by a fair bit.
Asda used to do some really nice standard cheddar IMO, but it seems to have changed. Though still better than the others just not by much.
As for mayo, I've always preferred sainsburys mayo - though I'm not a massive mayo fan. Others in the house have preferred hellmann's (except the time we got it from costco and it was almost like a mousse and weird as hell). That said we've been generally getting the sainsburys one for a while now and I think everyone now prefers it these days.
I've never been a brand snob, I'll happily eat the cheapest option if I prefer it. Apart from that, if the item is more expensive then cost/yum comes into play, probably with more of a bias towards yum factor even if I'd need to get the item less often because of that cost.