A mystery shop into the usability of 14 of the most high-profile on-line cars sites has found the majority to be average or poor in terms of content, ease of use and customer service.

The survey by the Interactive Media in Retail Group (IMRG) found two clear winners among the dotcoms, Audi and Autobytel, which were both judged to be “excellent, well thought out, user friendly, with great looks”.

The websites offered by Alfa Romeo, Land Rover, Nissan, Renault and Volvo all fared badly, with IMRG accusing them of being “poor, poorly constructed with limited use”.

The remaining sites, from BMW, Citroen, Ford, Honda, Jaguar, Jamjar.com and Vauxhall, were given an average score with IMRG recommending “more thought and investment”.

IMRG's 'mystery shopper' said of their findings: “Generally the sites are showcases, heavy on graphics making site performance slow. Usability was generally a poor feature. Only one site, Audi, enabled me to follow the instructions through first time without suffering screen rage.

“On the better sites details of financial packages allow you to put a value on your own trade-in vehicle and calculate your purchase costs.”

Of Autobytel's performance, IMRG says: “The results strengthen its position as a consumer's champion and success in taking the hassle and haggle out of car buying. Autobytel is continually improving site layout and design, ensuring a top position in our next survey.”

The sites surveyed and the 'mystery shopper's' conclusions:

Audi - www.audi.co.uk
I was extremely impressed by this site, particularly having struggled with some of the others. It was a dream to use and very simple to navigate. Brochure first to arrive.

Autobytel - www.autobytel.co.uk
Complete online transactions possible, but contact needed for certain options. Registration but no personalisation – just an opportunity to receive news and offers via your inbox.

BMW - www.bmw.co.uk
A good starting point to gain info about BMW and locate your nearest dealer, but unless you want to purchase a miniature car from the online shop you will have to go to your dealer.

Citroen - www.citroen.co.uk
Despite no online sales, the ability to download detailed specs as a pdf file was a bonus.

Ford - www.ford.co.uk
A poor site. It is possible to order online and had online tracking, but I wasn't impressed and wouldn't return to the site if I had really wanted to make an order.

Honda - www.honda.co.uk
Not a fancy site but I felt it at least gave me a good starting point to research a car and contact a dealer to pursue a purchase.

Jaguar - www.jaguar.com/uk/
A very classy looking site, but didn't quite have a transactional, interactive feel - at each point you are directed to contact your dealer via email.

Jamjar - www.jamjar.com
Useful site if you know what you want, but poor search results and few graphics.

Vauxhall - buypower.vauxhall.co.uk
Not quite a complete online transaction as your local dealer must contact you to finalise the deal. Unless you make a significant saving over the showroom price it may not be worth all the trouble. Site too slow.

Alfa Romeo - www.alfaromeo.co.uk
One of the more frustrating sites that failed to impress - I felt the site assumed you already knew a lot about its range of cars.

Land Rover - www.landrover.co.uk
No interactive features, info only site. I would need a brochure to review the vehicles and then maybe use the site to search for specific informatio or view the 3D graphic.

Nissan - www.nissan.co.uk
Gimmicky advertising site with little technical detail. Glossy overview.

Renault - www.renault.co.uk
Spent ages trying to get the most from this site. Finance details not explained too well.

Volvo - www.volvocars.co.uk
Went round in circles a number of times on this site, eventually managing to construct and save a vehicle, but usability lets this site down.