Pros:
Easy ability to format text in new email (bullet list, numbered list, bold text, etc.) which I really *love*. (It would be nice to see that expanded to include font color.)
Easy to attach audio file. Im not sure if Ill use that or not, but Id like to experiment with it. Seems like a good idea.
I really like being able to add reminders to email.
Cons:
Its complicated. That may not really be a "con", since the complexity comes because it has a lot of good features. But be prepared to spend time learning it.
Its buggy. This is the only reason Im not using it yet. A couple of versions from now, when the bugs have been ironed out, this may be a great email client.
Cant remove the "sent with Envelope" signature. That would be fine if there was a "pro" version you paid for that allowed you to remove the signature. Hopefully thats in the works.