I don't think that there is a definitive answer because everyone has different needs and requirements, so different policies suit different circumstances
for instance, if you holiday abroad regularly, then holiday cover is more appropriate than if you always take your dog caravanning with you in the UK
A higher excess might be more suitable if you are happy to absorb low cost bills yourself, and added extras such as behavioural and complimentary treatment might be influenced by your own opinion of these treatments
I have seen horror stories about nearly every company out there - sometimes it is a misinterpretation of the policy by the policy-holder, other times it is companies being inflexible or insensitive, but ALL companies are there to make a profit so I don't think any of them can be expected to put their customers needs before their own (although sometimes, they
do go the extra mile which is a pleasant surprise
)
I have yet to find a true like-for-like comparison between two different policies - they all vary slightly in the cover and exclusions; so it really is a case of deciding what you need, and then finding a policy that suits