We had Staysure. One of those where you only find out how good they are when you come to claim!
We sometimes check out "travelgo" haven't checked as a family yet but will be soon.. interested to know what you go for!!
We used Direct Line. I'm with them for car insurance and when I've needed to claim for that they were brilliant so I trusted them the same for travel. We ended up having to book another flight home when ours was cancelled and had to claim the difference between what we spent and what was refunded, they did that no quibbles.
Look at compare the market x