Honestly I would never purchase nor install an alarm on our coach. We've also felt 100% safe in it and when parked if someone is going to break in it they will and I doubt an alarm is going to stop them. While camping our two large dogs are with us and I'm always armed.
Not concerned about someone stealing my coach either. I have lock on the pin and you would need a big truck to haul it away, something I'm thinking most criminals don't have.
This is what insurance is for. As I've said if someone wants it bad enough they'll take it regardless of the alarm. Maybe someone with high end class A DP would want an alarm, don't think your average RV'r would. Good luck though.