I try to avoid the larger companies simply because they are trying to get the cream of the market. They effectively then get to dictate insurance prices due to their huge market share. It then leaves the smaller companies to offer policies which will include agreed values and modifications. That is why our cover is often fairly expensive. Direct Line is the largest, I am led to believe.
From my experience the smaller companies are also usually better to deal with. Here is a brief summary of my previous experience.
1. Norwich Union: really bad to try to get the details right and the worst company to deal with when some fool hit into the rear of my then 75. I'll never have anything to do with the NU again.
2. Esure: good but this year I switched and saved nearly £100 with Diamond!
3. AA: I wasted as much time on phone calls trying to get the inept staff to try to get my details correct. Switched cars and the next years quote was very expensive. They flatly weren't interested to match quotes (after 4 years with only a windscreen claim!).
4 Adrian Flux (Sterling Insurance in Norfolk) simply the best insurance company ever. Phone calls answered timely, professional and courteous service and very good prices. Best of all, great when it all goes wrong and its claim time (non fault, of course!)
5. Chris Knott: I have a friend who waited very patiently whilst his claim on his 75 was processed. It took a very long time and he did not get a hire car. I think they had problems a couple of years ago, but I believe that this should now be rectified.
Always make sure your policy has provision for a hire car- otherwise the company could drag their heels come claim time! Not improtant if its a second/ weekend car though.