Workspace snapshot vs. reload has already come up in a couple of other threads. It's a real hot button for me because I prefer the slower-but-newer behavior of OW 5.1.3 for my workspaces with volatile content.
When I launched SP4 for the first time about 10 minutes ago, I immediately checked two of my workspaces holding pages from two news sites. In both cases, I found up-to-date content.
It's too early to tell whether these workspaces get reloaded each time I switch to them or just at launch time.
Here are the earlier threads:
Tab rendering issues in sp1
[sp3] forums icons not updated