I got S418/S357 on all 4 boxes. Whole Home does not work with a HIC after the update. Hopper/Hopper connectivity is unreliable and mostly doesn't work. I went back to the old setup bridging one Hopper and Whole Home works OK. I reported it to Dish.
The only differences I see are smaller icons in the recordings screens and changes to the search screen.
Update - Hopper/Hopper connection just failed with bridging enabled.
Another complaint about this release is that there is no longer an "S" on programs in the PTAT folder if they are saved.
I like how it has the On Demand within the guide but why only History Channel and the premium movie channels (HBO, Stars Etc)?
From what I'm reading from you, I hope my receivers aren't next on the list!