I have to drive past Asda, Morrison's and Tesco to get to the nearest Sainsbury's to me. (There are also other branches of Asda and Tesco, in the opposite direction, which are closer to me than Sainsbury's). So I don't shop in Sainsbury's very often. However I like their products; they seem to have a better range of chilled and frozen meals than most of their rivals. I think of them as being quite a bit more expensive than Asda, Tesco or Morrison's though.
It's a 30-mile round trip for me to get to Waitrose so, unless I'm in that area anyway (e.g. when I've got a hospital appointment), I rarely shop there. I like their products but I find many of them pricey. They also don't stock many of the things I like. (e.g. I can buy lots of different types of canned curries in Asda but Waitrose don't stock any at all).
I hardly ever think of shopping in Iceland. I like some of their products (and I like their prices) but their limited range of non-frozen items means that I can't do a 'big shop' in there. (I've only got a 'table top' freezer, so I never need much frozen food).
I always regard Asda as the cheapest of the 'full range' supermarkets. (i.e. excluding Lidl and Aldi, where they generally only stock their own brands of stuff). However the quality of their chilled and frozen ready meals generally isn't great and their customer service is appalling, so Asda isn't my first choice for shopping.
Tesco seems a bit dearer than Asda to me, for much the same sort of stuff. So, despite Tesco being the easiest big supermarket for me to access, I don't get in there very often.
Morrison's is where I do most of my shopping these days. It's always very quiet on a Saturday evening, when I usually shop there, with no more than half a dozen other customers in one of their largest stores. So I feel quite safe in terms of Covid risks. Their range of products is quite good and their prices aren't that much dearer than Asda's. Further, during non-Covid times, I enjoy eating in their café, largely because their staff are so friendly.