I used PURE for the past 4 years for home, auto, and umbrella coverage, but recently switched to Cincinnati.
As others have said, PURE has been around for a while, though was acquired two years ago by Tokio Marine Holdings.
Since the acquisition by Tokio our premiums have increased 50-100% each of the past two years, despite filing no claims and having no changes or other extenuating circumstances. After another 50% increase for the coming year, I shopped around and chose Cincinnati, which seemed to have good references and was significantly less expensive than the PURE quote for the coming year.
My understanding is that Tokio doesn't want to be in certain businesses, such as insuring homes in coastal areas, and will only continue to provide coverage if they're able to get insanely high prices. They apparently designated my entire state as a 'coastal area.'
YMMV, especially if you're not in a coastal area.