I've been running dropbox on my home laptop and work desktop for a few days now. It seems to be working amazingly well. Very user friendly, very quick. I have moved my data folder for Things (a GTD application) to the dropbox folder and after pointing the application to where its data had moved to it has worked flawlessly. My home and work machines are perfectly in sync. Now there are many other sync options but this one has the advantage of not having to remember to do anything, ever. The application at home and work are always in sync. I do not have to remember to press "sync" or close an application or anything. Remembering to sync before going home has be the cause of the failure at all previous sync strategies using a variety of sync software. Dropbox syncs continuously though in realtime.
I have also synchronised my Journler application. It has worked flawlessly again, even though I have the application open on 2 machines simultaneously (although I am only modifying one at a time obviously).
Papers has not been so smooth. I still need to investigate whether it is syncing properly or whether I am just imagining that some things are not updated. It could be that the application doesn't write some data until it is quit, that would certainly cause problems I guess. More experimentation required.
I have also moved my folder of perl scripts to the dropbox folder. Not only does this sync between home and work but includes a versioning protocol. So if I modify a file I can go back and examine previous versions of that file and revert to one if I have messed things up. I know that svn etc do something similar but this has been idiot proof and has not required all the messing around to install that subversion seems to take.