ALL that matters is if the monitoring company is licensed in your state (most states requires this in the US), and UL Rated. If it is UL approved service, you have the proper permits, etc then you will have ZERO problem with claims. If your insurance company bitches, take them to the state insurance board in your state, they'll cry uncle in approximately 5 seconds flat.
Here are some other things to know. UL Rated monitoring should cost NO MORE THAN $9.00 a month, if you pay more you're getting gouged. NEVER EVER EVER IN A BILLION YEARS sign up with people like ADT where you'll pay some ludicrous fee like $45 a month, plus a land line, plus MORE if you want to use wireless. Don't EVER sign a contract, you can get $9.00 UL monitoring on a pay-as-you-go basis.
The big firms will try to 'give you' all sorts of 'free' equipment to induce you to their overpriced service, its not worth it. ADT might give you $1500 worth of stuff, but they'll lock you into an expensive 3 year contract, and there WILL be hidden fees, little extra things you won't get that you need, etc, so by the time your done the cost will be very significant AND you're still overcharged.