@Michael Baum I would love to!
To my understanding (having had some conversations with underwriters from several different companies) there is nothing different between the coverage offered by Proper, Foremost, CBIZ, Allstate, Progressive, Travelers, American National, Liberty Mutual, Pure, or any of the other insurance carriers.... in fact the underwriters, E-suite, and actuaries from all of the companies hop between one another every few years. This is one of the reasons that property/auto/commercial/BOP policies are cyclical (company "A" is the cheapest today, next year company "B" is the cheapest, the year after it is company "C" and within 5-7 years company "A" is the cheapest again)
Now that doesn't mean that every company is going to insure whatever business you send them. In fact most carriers only like to actually win 20-25% of the quotes that they issue. and some companies have restrictions on location (city, state, and even neighborhood), type of house, build type, ownership type, what the property is used for, etc...
So they all offer the same stuff as far as the policy goes, the difference come in when the landowner decides how much coverage he/she/they want in each specific line of coverage.
By letting carrier XYZ know that your property is going to be used as a STR or an Airbnb they are able to charge you the appropriate monthly, annual, bi-annual premium so that they the insurance carrier feels like they can take on that risk of business.
Proper Insurance has a great product, they know it and they charge a premium because they have set up an awesome niche that they work well in. They have also done a really good job marketing themselves in that niche. similar to PURE insurance marketing to the "luxury/high net worth" market. similar to Geico saying switch to us and save 15% or more... every company has their marketing gimmicks.
So the best practice is to build a good relationship with a knowledgeable insurance agent (there are pros and cons to using an independent agent or a captive agent).