The data plan is a non issue, either will work fine with exchange.
I'm having this same exact problem. This will be a big issue for those of us who need use this phone for business purposes. Looks like I might be going back to a WinMo device afterall.
Ok, I just resolved the viewing attachment issue, under account settings I unchecked the box for "Use secure connection (ssl) now I can view all attachments just fine.
I hope this works for the rest of you.
Unfortunately for me our corporate exchange server requires the SSL connection in order to allow connectivity... big security risk if everything is shipped around unencrypted. Tried but couldn't open connection to the server without SSL.
They say its a national problem. I'm on business plan. They claim fix will be posted. Mine still not working. Even emails forwarded from droid come as attachments. So can't open those either.