The US-04 is a high flocculation yeast that's supposedly known for fast fermentations. The US-05 is low to medium flocculation with clean flavors. The 04 should be better by defenition at midwest site.
I pitched s04 for the first time on Friday. It's fermenting, but all I have is a thin layer of bubble popping krausen. I'm more accustomed to the thick trying to crawl out the airlock fermentation.
Every fermentation is different. Krauzen action can go any number of ways. I've had fermentations with s-04 where I too was a little perturbed by the seeming lack of dynamics and others where I was hoping the volcanic eruption would soon subside