I thought I had replied, but it never showed up.
I am running 4.052 in one office on about 7 computers. Echoing what every one else has said, it is faster and seems stable. I have not had resource issues.
The backup does not seem to provide regular backups automatically, there are some weights that incorrectly show up in red, minor problems overall. Early on, there were some problems about logging in from a non administrative windows account, but that is no longer an issue.
A new release notice came today, looks like they are tackling the synch problems, it was clearly stated before that synch was not working. I had not tried it.
I would probably install the program on the server and it will convert the database. It may require as stated above that you have actually installed 3.7.15 first.