I have been testing the merge replication from Sql Server 2005 for a client. The truth is that I was very impressed with it. This thing works very well (at least with the requirements we had) and it's all a matter of configuration. I had some difficulty setting up the subscribers running on each client (pull replication). The agents would constantly fail due to security reasons. After a lot of trial and error and finally reading about it here I was able to have a secured model and make replication work. I must say I didn't have a domain set up...