FWIW, we zipped through 37 at about 11:00 am with absolutely no issues! Just before making the decision on I-80, we saw the traffic flow and I-80 was starting to back up whereas the 37 was smooth.
Coming back, I opted to go through the Bay bridge. The traffic on going north was horrendous at Golden Gate Bridge. Getting out of SF was heavy with street traffic but once I got going smooth all the way to Sac town. But West bound was heavy too.