I am by no means an expert just yet, although I am hoping to dig in even more as I get my more opportunity with the product.  I did try a large file transfer within a Groove workspace and it was surprisingly fast across the LAN.  The file was about 500Mb and it was completed within 10 minutes.  Somehow I expected more delay than that.  Not sure if I would try such a big file across the Internet, well unless I knew the connections on both ends were fairly good.

What does SharePoint Workspace 2010 do?

This application is billed as the offline client for Sharepoint, however it still supports work group style collaboration that was available in Groove, but adds SharePoint functionality.

Personally I have found that disconnected collaboration works very well in both Groove and Workspace.  Suppose I am going to work on a project with two other individuals and they do not work for the same organization as I do.  Workspace 2010 (and Groove) allow me to create a collaboration session (or workspace) for the project and invite them to join.  When they do this all parties can trade files, messages, and other information.  Without the need to worry about firewalls or access rights.

Since all the content is encrypted share away, there is not too much need to worry about file transfer (although there is always some need).

Another way I have used SharePoint Workspace (and Groove) is to trade files with my other computers.  Suppose I am working on something at home and need to get it to the office.  Sure I could use a flash drive or cart my laptop to work.  Or I could put it in a workspace to which both of my computers belong.

This scenario might be good for those who are occasional road warriors.  In the office most of the time, but attend trade shows or other events from time to time.  Maybe they have access to the VPN, but if they are occasional travelers they may not.  Using a tool like SharePoint Workspace, the traveler could use a workspace on their work computer and on their laptop (or a company one that they checked out) to allow access to needed files while on the road.

Does it work?

So far, in the testing that I have done it works very well.  I have a few work spaces configured to trade files between my various PCs.  Another nice feature is that you can create an account (associated with your Live ID unless a Groove Server is used) and open or subscribe to as many work spaces as you need without the need to log in separately for each one.  Of course the multiple account scenario seems to be supported as well.  I tried that for a while, but didn’t like logging on to other identities to work with certain files.

When Office 2010 gets to you (it is already available on TechNet and MSDN and maybe even to business) I recommend giving SharePoint Workspace 2010 a look.  It might be just the collaboration tool you need, both with and without SharePoint.