I have mail set up and it seems to be syncing well. I have two email accounts set up: my iCloud account and a gmail account. I used Mail.app to send a test message from iCloud to GMail and it showed up instantly, but in both my inbox and in my junk mail folder. I marked it as "not junk" and then there were two copies in my inbox, linked into one conversation.
I cannot get my calendar or contacts to sync though. I have enabled it in Sync Services but no soap. My inability to get my contacts to populate in Outlook from iCloud is probably what caused my test email to be classified as junk.
iCal and Outlook *appear* to be syncing, but it's only local, not through iCloud. I can tell because nothing goes to my iPhone. Additionally, when I create an appointment on my iPhone it appears immediately in iCal but fails to appear in Outlook. I must conclude that there is still not sync between iCloud and Outlook for calendars and contacts.