>So, do you know the difference and what speed (or response) impact has each one?

SOAP 3 client is slower but faster on the server side either for ASP or IASPI. I've been told that for the client, the difference in speed is because of focusing on a better quality instead of performance in regards to a different HTTP stack used.

I've seen a big difference from the result time. The performance of increase from the server side is nice.