Devastat, would you mind emailing support (
omnifocus@omnigroup.com)? Sync via our server should be much faster than what you're experiencing, and I'm confident that we can get whatever issue is slowing things down fixed for you.
A good first troubleshooting step might be to go to OmniFocus Preferences > Sync on your Mac and click the button to "Show Clients". Duplicate client listings can prevent OmniFocus from compacting its database, making sync slower even when the overall db size is still best measured in KB. If you have duplicates but aren't sure which ones to delete, just send support a screenshot and we can get you sorted out.