I've just upgraded to the June 15 build of the DS and still have mostly the same issues with my Palm Pre WebOS phone, but my experiences with Android and iPhone have been perfect.

On the Pre, I'm still getting the following issues:
The FROM and REPLYTO fields are not being populated when sending an email to someone outside of my GroupWise system. (To me this is a critical issue, but I'm the only WebOS phone in my building).

When sending to someone inside of my GroupWise system, recipients usually see in the From column the "Sender's Name <sender@domain.com>." This may be unique to domains set up as mine as we use a mail.domain.com email address scheme, but I'm seeing "Sender's Name <mail.domain sender@mail.domain.com>."

Not sure if this is an issue, but the entire contents of the Global Address Book is syncing to my phone's address book. I have a Mobile address book that I usually use to just sync the people that I usually communicate with. I'm not opposed to having the entire address book syncing as I'm with a smaller company, but don't necessarily want everyone in my company as a contact. The previous build did not do this, it is new for the June 15 build.

On the flip side, the emailing a copy of every message to myself and a not previously mentioned, duplicate notification alarms have gone away. Good work!