Which car insurance company can be trusted?

My car insurance renewal price has gone up by £400 with the company I have been with for years.

Money supermarket has come up with cheaper quotes for the following companies by around £300-400 less:

• First alternative
• Direct line
• Esure
• Sheilas Wheels

Are these companies good value and reliable if needing to get hold of them for claim?

The defaqto scores are 5 stars