I have yet to discern a single redeeming feature in it.
It looks like hell.
It goes wonky and makes it difficult to move my cursor back to the message title or message content fields when I try to paste large numbers of addresses into the send fields.
Google moved access to contacts out of Gmail where it belongs and into its own separate function where it's a pain in the ass to get to.
New Gmail doesn't seem to do anything better than the previous version, and does some things worse, and again it looks like hell.
But of course they're forcing it on everyone and the time period where I could revert to Gmail that actually works seems to have ended.
I'm still auditioning replacement services while hoping someone will come up with a style extension that brings back the old inbox look -- the new one literally makes my eyes hurt -- because changing over is going to be such a pain in the ass. But not as much of a pain in the ass as putting up with this.