Chrome Sync is a dog, no doubt about it. I'm converting from Firefox to Chrome out of security concerns: Chrome sandboxes its content to insulate web content from the computer, while Firefox doesn't. But bringing over my nearly 8000 bookmarks is causing problems.
It appears that the way Chrome works is that, right when you start it, it will submit about 100 bookmarks, give or take. Then, maybe 2-4 hours later, it will repeat this process. So, if I just start up Firefox, I'll be waiting...2 weeks or so, to get synced. Hell with that. By the way the slowness of it is documented here.
Now you might think, use Xmarks! Yes, some of us have Xmarks, which preceded Firefox's own sync mechanism by some time. Xmarks was a godsend for those of us wanting to have bookmarks shared across multiple machines. The problem is, I tried this, and got duplicate bookmarks all over every copy of Chrome. So I uninstalled Xmarks from Chrome, nuked all my bookmarks in Chrome, picked one canonical source, and imported from Firefox on that machine.
So, what can you do to speed it up? Here's a little hack I just realized, for Windows users: Create a Scheduled Task. Make it start up Chrome every 3 minutes (you have to type in "3 minutes"). Make it shut down Chrome after 2 minutes. Now you can speed up those iterations, without manual attention. This should sync up 8000 bookmarks in about 4 hours.
I don't yet know what happens on the receiving ends, BTW, but I think these will gobble up the bookmarks from the server much more readily than they got uploaded.
Edit: Here's another thing I don't like about Chrome's bookmarks: No tagging support. Now, you can get plugins to help with it, but the lack of built-in support means that they won't migrate over using XMarks. Because of this I actually ditched Chrome and went back to Firefox. I just hope Firefox ups its security and isolation game soon.