I was at the matinee yesterday (actually, two rows behind BroadwayBeebe), but I'm just getting the chance to express my views now. Overall, I felt the production was good, but not great. I understand (and am fine with) the fact that this was a concert presentation, but I think I've been spoiled by how polished other Encores! shows have been lately, even with the short rehearsal period (1776, It's a Bird..., Merrily We Roll Along, to name a few). The concert nature of Assassins really showed in "Another National Anthem".
This was my first time seeing an Encores! show from the orchestra (I'm usually in the cheap seats in the balcony), so I had to adjust to the fact that most of the sound was coming from the stage and not some elevated speakers. That, and the fact that I could see the actors up-close, I think, affected my overall view of the show.
To start with, I thought Ethan Lipton's performance was really as poor as others said it was. It was as if he was painfully aware that he wasn't the strongest singer and, as such, sang in a conspicuously diffident, uncommitted manner. That carried through to his acting, as well, which made him cringeworthy to watch. It looked like he felt deeply uncomfortable with the fact that he had been cast in the role and carried that discomfort onto the stage with him.
The standouts for me were Shuler Hensley as Czolgosz and Danny Wolohan as Byck. Both seemed to really get at the depths of their characters (Side note: Did Wolohan remind anyone else of Andrew Scott from Sherlock?). Steven Pasquale was beautiful in voice, as usual (as was Clifton Duncan), though I'm not sure he had the time to really immerse himself into Booth, which is too bad, given Booth's presence throughout the show. I love Victoria Clark, and I thought she was quite funny as Moore, though I wouldn't lay on the lauds as others have on this board. Everyone else was just fine, though I didn't feel the ensemble provided the undergirding support the show needed.
As has been mentioned before, the staging was a bit stilted and some of the book scenes really dragged, but I enjoyed Sondheim's music and would be interested in exploring the cast albums of the show's earlier incarnations (the Encores! production was my first exposure to the show). I'd also love to dig into the the two Byck monologues, which I feel are far denser thematically than they may appear on the surface.