I am not sure if this is a first, but it sure seems like a first in the industry. Most service providers who stop DDoS attack, do not provide any detailed logs, IP information, etc. on the attack. Reasons vary from inability to stop all the malicious packets (which might filter through), to secrecy, etc.
However, I think Staminus may have just raised the bar. I just came across their forum post (which is quite old), but I was totally taken back. Staminus is now providing detailed log reports, etc. from the client’s Control Panel.