Some of the features I personally love include the following:
- Inline view of message attachments -- this means I don;t have to open an email to get to the attachment; I can directly open the attachment from the list of messages in my inbox.
- Inline delete -- if there is an email I don't need, I can just move my mouse to the right edge of the message and click on the trash can to delete it.
- Auto reply -- on some email messages, you may see some auto-reply choices: just click the response you want and then click send!
- Calendar, Keep, and Tasks on the same page -- so handy to be able to have an email message open and right there in the same tab be able to open my calendar to add an event, Keep to make a note, or Tasks to add to my to-do list!
- Snooze -- well, I love the IDEA of snoozing an email (essentially marking that email to come back and tug you on the metaphorical sleeve as a reminder to deal with that message); I say I love the idea because it is only available if you use Conversation View for your inbox (which I don't).
Try it out, see what you think! To help you, I found this great overview video put together by another Google for Education Certified Trainer. Watch it to see the new Gmail in action!