We run into problems with the responsiveness of the user interface. This has been a problem in versions 3 and 4. When there are a lot of activities processing, the UI will hang. We've seen this in the OSX and Windows clients for quite a long time now.
Currently, for instance, I cannot manage my client UI on one machine running OSX. This machine had a large upload of about 5gb of new data to the file system and has been unresponsive for over 24 hours - unresponsive in that selecting a UI option, like click on Activities, may take up to 10 minutes to affect the UI. We've seen the same situation in both V3 and V4 clients in OSX and Windows. The sluggishness also makes correcting file conflicts a maddening process.
Is there any hope for a future solution like moving the UI to its own thread which isn't blocked by the other activities?