I'm on my second attempt syncing from scratch, this time using Dropbox sync. A couple thousand items synced relatively quickly, but now it seems like it's running into problems. I am currently watching sync take several minutes to increment the count for "updating remote item". It succeeds in updating one or two, then throws the following error every time:
"Sync target is locked - aborting API call"
At this rate, my 500 note sync will get done in a few days, perhaps a week if I babysit it!
If I recall correctly, I simply gave it some time. However, Dropbox sync was faster and smoother than Local File sync, which I believe shares some commonality with WebDav sync. Even if it doesn't, I saw similar performance complaints between the two.
Most importantly, since the initial sync, Dropbox sync has been quite reliable and pretty fast for me.