Do the ServiceStack client libraries send a gzip header through?
Accept-Encoding: gzip, deflate
Just wondering as IIS does do some lovely dynamic compression on json and xml responses if setup correctly. If any is interested in setting this up in IIS I highly recommend reading the following: http://goo.gl/QLpgvt
Yeah it adds compression headers by default, can be turned off with client.DisableAutoCompression = false;