I have an application that performs a little slow over the internet due to bandwidth reasons. I have enabled GZip which has improved download time by a significant amout, but I was also considering whether or not I could switch from XML to JSON in order to squeeze out that last bit of performance. Would using JSON make the message size significantly smaller, or just somewhat smaller? Let's say we're talking about 250kB of XML data (which compresses to 30kB).