Which? found that only a third of members sayid they trust price comparison sites to find the best price regardless of the supplier.
Richard Lloyd, Which? executive director, said: “We’ve found that many people just don’t trust comparison sites to get them the best deal and from the results of our research it looks like they are right to be sceptical.
“Price comparison sites claim to do all of the work for you but we found they don’t always guarantee people the best deal or even the right one.”
Which? put this to the test by looking for the cheapest quote from different sites for the same high risk car insurance scenario and found it can differ by more than £1,500.
It asked more than 6,000 Which? members to rate eleven of the biggest names in price comparison sites.
MoneyExpert.com and MoneyFacts.com were ranked the highest with customer satisfaction scores of 46% which the consumer champion said was a low score when compared with other areas of personal finance it had rated.
MoneyExtra.com was the lowest ranking comparison site with a customer score of 28% receiving two star ratings for all categories.
Market leader MoneySupermarket.com, which had an annual turnover in 2012 of £204.8m, was ranked fourth in the table.
The Which? survey found members who used comparison sites visit an average of two sites before making a decision and one in eight feel the need to visit four or more sites to get the best price.
Lloyd said: “We want comparison sites to treat customers fairly by being upfront that they don’t cover the whole market and more transparent about what is and isn't included in the policies they're selling.”
