Looking forward to the release. I’ve had similar issues as Trace. I think the top button only deletes the cache for the specific blog. Although, my issues go deeper that the cache for the Feed isn’t updating on new posts on my multi-site blogs. Once I clear the cache it does, but otherwise it’s not. Might be a configuration issue too I imagine.
I’d love some more detailed info on best practices configuration for WP Super Cache too. It’s got so many options now that it’s hard to know the difference and what’s best for a specific configuration and I’m sure you know this info.
Regardless, great plugin! Has saved me many times.