The thing with Chubb is that they assume you're honest.... which is a good thing. When I lost a Breguet watch in the sea their response was 'where should we send the cheque?'. The fire at home was a £40k loss - all settled (rapidly) without so much as murmur from Chubb. I can't rate them highly enough. However it's only when you have a claim that you realise you get what you pay for - paying years of premiums without a claim makes them appear expensive.
Absolutely right. I use NFU for the same reason. It's all very well buying insurance on price, but if you ever need to make a claim then it's quality of service that suddenly becomes the important thing. I've only had cause to use them on a couple of occasions, and both times they paid up immediately and without question.
The cheap insurance companies are able to drive their premiums down because their claims handling policies are extremely rigorous - they do everything they can to avoid paying.
As always, you pays your money and you takes your choice.