Waitrose has been rated the best UK in-store supermarket in consumer group Which?'s annual satisfaction survey.
The John Lewis-owned chain scored five stars in almost every category, but was ranked joint worst for value.
It's the second time it's been voted the top grocery store, despite budget chains Aldi and Lidl being ranked best for value.
"The quality of fresh products is the most important factor when choosing where to shop in store," said Which?.
"There's clear room for improvement for the 'big four' - Tesco, Sainsbury's, Morrisons and Asda - as they continue to trail behind Waitrose and Marks & Spencer for experience, and behind Aldi and Lidl on value," pointed out Harry Rose, the editor of Which? Magazine.
In the survey of more than 14,000 Which? members, Asda was rated the worst.
The consumer group found that shoppers like Asda's range of goods in store, but clearly want more recyclable packaging and products without packaging, as the store gained only one star for this aspect.
The survey revealed that Asda provides neither the noteworthy store experience of Waitrose or M&S, nor the value of Aldi or Lidl. Asda scored just two stars for the quality of its own-label products.
The store hit back by pointing out that none of Which?'s members had visited one of its stores recently.
An Asda spokesman said: "We're always happy to take feedback - but as 70% of the Which? panel surveyed haven't visited an Asda in the last six months, we don't believe their findings are a true reflection of the experience of our 18 million weekly shoppers, who are looking for a supermarket that provides great value, range and service to customers working to any budget.
"We are proud that our customers are recognising this, with our online grocery service growing at three times the rate of the market.
"We're constantly striving to improve our offer to our customers - be that through the efforts of our hardworking colleagues, the 1,272 new products we launched in 2019, the 530 awards we won for quality, the 8,000 tonnes of plastic packaging we removed from our stores or the 22nd annual Grocer Award for being the best-priced supermarket."
M&S lived up to its reputation for quality when it comes to food and drink, scoring five stars for both its own-brand and fresh produce.
But its overall customer score of 73% left it languishing just below Waitrose, not managing to quite match its rival's in-store experience or product range.
Aldi and Lidl were rated best for value, both receiving five stars. The budget supermarkets are seen as the best for those wanting more for their money, with rock-bottom prices making customers much more forgiving of their less-impressive traits, such as long queues, or unhelpful or hard-to-find staff.
One Aldi customer said: "It's not a pleasant place to shop, but value for money is exceptional."
Morrisons and Sainsbury's came in mid-table, with Tesco sliding in just below and Iceland coming in second-to-bottom.
Shoppers told Which? that they like Iceland's value for money, but this was not enough to boost its score overall. The supermarket failed to impress with its fresh produce or product range, and got just one star for availability of recyclable packaging.
The Which? study also found that when shopping in store, people were most frustrated by waiting for help at self-service checkouts (26%) and by a lack of staffed checkouts (25%).
Here are the supermarkets' overall customer scores, according to Which?. They were rated for store appearance, product range, queues, staff availability and helpfulness, quality of own-label products, availability of recyclable packaging and value for money:
- Waitrose - 76%
- Marks & Spencer - 73%
- Aldi - 71%
- Lidl - 67%
- Morrisons - 65%
- Sainsbury's - 64%
- Tesco - 61%
- Iceland - 60%
- Asda - 58%