Rackspace policy is obviously better since they charge a lot more.

My host has:

    If Liquid Web is or is not directly responsible for   
    causing the downtime, the customer will receive a 
    credit for 10 times ( 1,000% ) the actual amount of 
    downtime. This means that if your server is unreachable 
    for 1 hour (beyond the 0.0% allowed), you will receive  
    10 hours of credit.

Rackspace has:

    Rackspace Guaranty: We will credit your account 5% of 
    the monthly fee for each 30 minutes of network   
    downtime, up to 100% of your monthly fee for the 
    affected server.