After only half a day of testing and use, here's my very preliminary thoughts on the new SiliconDust HDHomeRun ATSC 3.0 4k tuner. Of course, there is no ATSC 3.0 in the Bay Area yet, so this addresses only 1.0 performance.
As mentioned, I'm in the east bay Tri-Valley, which is one of the most difficult areas for reception because the nearby hills between Sutro and here create lots of dynamic multipath that is very difficult for antennas and tuners to reject. Anybody in a valley with surrounding hills - wherever they may be - would face similar problems, though.
The best tuner I've found for dealing with this type of rapidly changing, complex multipath is the LG OLED internal ATSC 1.0 tuner. It manages to figure out the primary signal and lock onto that better than anything else. Still, there are times when signals are so unstable that reception is nonexistent or intermittent and unusable.
The HDHomeRun Connect Duo that I tried was significantly inferior to the LG tuner. In fact, the Duo really wasn't acceptable because reception was too unstable and unreliable. It's a much older design.
The brand new 4k tuner is much better than the Duo, and probably close to the LG internal tuner. It's had a couple of firmware updates in the last day since I got it and those seem to have improved its performance as well. It's possible it will get better with more updates. Of course, the 4k should be dramatically better once there is 3.0 transmission available, as that's specifically designed to combat multipath. Also, for those without multipath issues but facing just low signal levels, my sense is that the 4k is excellent at sensitivity to weak signals, maybe the best currently available (low signal levels are not my big problem, so I'm interpolating to arrive at that conclusion from its performance with the weaker Sacto stations, which also have some multipath here).
As mentioned, I'll also be trying out the Televes MIX Dat Boss LR antenna to see how it deals with the multipath situation here. I'm hoping that will be an improvement over the small, 15 element horizontally stacked and phased UHF yagis I'm currently using. Yes, I've tried the long single boom UHF yagis and they did not seem to work as well as the stacked shorter yagis. We'll see how the Televes turns out.