My takeaways..
First, Comey said he was afraid Trump would lie about what Trump said. Zing! In fact, either Trump is lying or Comey is lying. Comey says that Trump invited Comey to dinner and asked for Comey's loyalty. Trump says that Comey requested the dinner and that Trump never asked for Comey's loyalty. One of them is lying. My sense is that the public is more likely to believe Comey than Trump.
Second, it doesn't really matter if Trump asked for Comey's loyalty. If all they have on Trump is what he said to Comey, then it's not enough. Comey says he interpreted it as an order from Trump. I don't believe Comey really interpreted it that way. The Republican Senators completely failed to ask the correct followup questions. They should have explored with Comey whether he would have done anything differently if Trump had explicitly said, "Director Comey, I order you to drop this investigation." Of course Comeny would have behaved differently in that case, which means that he didn't really think Trump was giving him an order.
Third, McCain is losing it. His rambling questions reflected a lack of understanding of the most elementary parts of the investigations. Fourth, McCain is losing it. Oh, wait. Did I say that already?
Fourth, Rosenstein's reputation is not likely to survive the investigation. Comey testified today that he told Rosenstein about Trump's loyalty request before Rosenstein wrote the memo about Comey. Unfortunately for Rosenstein, he is just an expendable satellite.
Fifth, Comey got his revenge and showed that he is more clever than I thought. He revealed that he authorized leaking information about his loyalty dinner with Trump. He said that he did so, in part, to force Rosenstein to appoint a special prosecutor. See the fourth point above.