Very interesting post and nice discussion.
I would also like to see where MS is going with all their Sync technologies, is there going to be some unified platform eventually?
You could use SQL Server Merge replication for most of the scenarious, it is very flexible and out of the box, it works with mobile devices Compact Edition and Express versions of SQL Server. Deploying stored procedures and making changes is easy and fast, just put it on a publisher and all clients get it, depending on the rules. When disconnected it works locally, when connected, SQL server automatically detects connection and starts synchronizing and it takes little effort to configure and no need to learn new API, which could change several months from now.
And there is Live Mesh for other things (like files), and I think Live Mesh team promised to open their APIs as well.
The good thing about Sync Services is that you don't need SQL Server license for Database Publisher and you don't need to replicate to the cloud.
Could you please point any other benefits, advantages, or disadvantages?
Thanks!