I also sat in the last row of the rear mezz (the $27 tickets) and the view was absolutely fine. At intermission everyone around me was talking about what a great view it was for the price.
"How is the Rear Mezz for Curious Incident? Would you say I should splurge to get center mezz?"
Just echoing the sentiment others have said. Those $27 seats are excellent for this show. Seeing it from afar makes the overall effect of the set really hit you.
I've seen the last 3 shows at the Barrymore from the rear mezz (including the dead-last row for BETRAYAL) and never had any issues with sight or sound. It's a smaller theater and the rear mezz is absolutely fine.
The view was just fine. Actually is was in some ways better than sitting orchestra because you can see some of the things he draws on the stage floor more clearly. But the sound quality was not great in the back. I often had to work quite hard to hear them, and I'm young.
I saw it early on from the $27 seats, and I don't recall having any trouble hearing. I concur that the view is fine, and I would aim to be in the center if possible.