Who do you all think is going to take this one? I think this is the closest race. I could easily see Daveed taking it home (my personal choice), but Groff and Chris Jackson also have a good shot and Christopher Fitzgerald could always be a surprise win as well as he was very good in Waitress. Also, I have to mention the depth in this field this year. The fact that people from Billy Porter in Shuffle Along to Gavin Creel in She Loves Me to Isaiah Johnson in The Color Purple are all off the list, not to mention the other Hamilton actors, it was really an outstanding year for this category.
Edit: supporting actors was a strong category though. If Daveed doesn't win I think it will go to Fitzgerald because the only way I think he won't win is if Hamilton votes are split.
I'm predicting Diggs, but hoping for Jackson, even though I'd be fine with Diggs. Jackson just brings down the house with One Last Time and I had so many goosebumps.
My pick would be Daveed. I enjoyed Groff's performance, but I don't think he should have made it into the category over the other names you mentioned. I also think Adam Kantor deserves recognition for the work he's doing in Fiddler.