Saw them 48 hours apart Christmas week, and enjoyed both immensely. They actually have zero in common, other than appearing in the same B'way season. "Evan..." is a show that will be beloved to/by many. It strikes emotional notes, both daringly and gracefully, and manages to do many astonishing things, including to turn a liar into an empathetic protagonist unlike any seen on the B'way stage, No, not remotely like "Next to Normal," which I believe is actually nothing like DEH, in the final (storytelling) analysis. "DEH" has that access, that leading role that we can't look away from, can't help but invest in because we see some small part of ourselves in him. "Comet" is closer to a "Candide" -like experience -- especially the 1st Hal Prince BAM "Candide" some of us saw in the 70s ensconced at the B'way theater. Malloy is a musical theater iconoclast, and no matter what you feel at the intermission, I say: hang on until the final 15 minutes, when the evening's structural design pulls the threads together for a beautiful, satisfying conclusion that we suddenly realize was set up from the moment Groban sings "Pierre." It's not a show for everyone, okay, but I'd argue, maybe a production for most people. It's just unlike anything else (currently), making "Hamilton" seem very traditional in comparison (I say that only in terms of cataloging theatrical shorthand employed by the productions). "Comet" also has one of the most gifted casts we've seen, at least since ... oh, "Hamilton." Not that "DEH" does not. But the company at "Comet" becomes the show, whereas in "DEH" it's Platt and some wonderful support.
For any serious fan/advocate/aficionado of the musical theater both are unmissable. That's the bottom line for me.
"I'm a comedian, but in my spare time, things bother me." Garry Shandling