It's not bad. I like the look. But there are some MAJOR problems:
a) Please get the Zoom plugin working. This is critical in the current working environment. Literally cannot use it until you fix this.
b) The way real estate is used on the email list is really BAD. 1) Please allow turning off of preview in the email list. The two current options are useless as all they do is take screen space. 2) Need to be able to remove categories in the email list, i.e. today, yesterday etc. 3) Font on email list is too large. These three items are a big cumulative problem that desperately needs fixing. I'm frankly amazed you have gotten this far with such an obvious interface design flaw, which seriously inhibits seeing enough emails at a glance.
c) Click to add appointment is super un-intuitive. You should be able to click and enter info directly
in the appointment
d) Dragging emails to folders in different email accounts doesn't work - eg one outlook.com account and a gmail account