The siege program is actually quite comprehensive.
Once the siege script is blocked, or fails due to rudimentary security features on networks. It'll come up with a report of the siege.
The siege includes great diagnostics.
Here is an example of one of my runs on the hpa.edu external IP.
Elapsed Time: 424.33 seconds
Data Transferred: 18.03 GB
Response Time: 2.78 seconds
Transaction Rate: 4017 trans/sec
Succesful Transactions: 1,704,000
Failed transactions: 700
Longest Transaction: 45.24
Shortest Transaction: 0.27