You will tend to find that a person's opinion of insurers, in general, will all depend on the way in which such companies have treated them in the past. I guess this is the same for most things in life really. But the most important factor in this decision making process usually revolves around the experience of having to make a claim through the insurers.
This is where all insurance companies really are not the same. Although all insurers are obviously out to make a profit, at the end of the day, they ought to be judged the most on how well they handle the claims that come in from their customers.
Insurance companies need to have a claims department that deals with any claim expeditiously and courteously. Moreover, they need to make sure they use clear and plain English to set out what exactly is covered in an insurance policy and what is not.
Some insurance policies can be particularly difficult to decipher and you may feel that you have no chance of understanding it fully unless you were a contract law expert. This should not be the case. Remember that you have a two week cooling off period to go through the policy, once taken out, and you ought to use this to ensure you are 100% happy with the product you have purchased.
If there are any aspects of the policy you do not understand - phone the company and have them explain more clearly. The more people that do this, the sooner they will get fed up and change the wording accordingly. If you are not happy with the policy, do cancel it and find one that is clearer and better for you.