If the major change is going to be a new control panel, and a different way of accessing support, then just say so.
I recommended them to several friends and colleagues, but from what I've seen of Rackspaces offering I wouldn't be able to do that with them.
RIP Slicehost :(
Also the fact that I haven't received the email myself is not reassuring at all.
I am not going to just sit around and remain without a predictable migration path, be it a migration to Rackspace or elsewhere.
I just have a little hobby server running on Slicehost. I feel sorry for people who are running businesses there. :/