Syncdocs can sync more quickly than the Google client. However, in my experience Dropbox (which uses Amazon S3 servers) is faster than the Google servers.
Another reason Dropbox is faster is that before uploading your file, Dropbox checks to see it any other Dropbox user has uploaded this file before. If so, it does not upload your file again. This practice, known as deduplication is smart, but it trades off speed for security. Your files cannot be encrypted privately as the server needs to check if anyone else has the same file.
Syncdocs uploads are slower, but more secure: Syncdocs always uses encryption and uploads your file to your private Google store. If the file is encrypted, it is also stored encrypted online and also has a tamper detection system built in.
There's more on other speed issues in the Syncdocs FAQ.