Meerkat Testing ISO question

[seattlechaz]

Greetings:

I downloaded and hash checked the Maverick Meerkat alpha then installed
it in Virtual Box.  Then, as is my custom, I installed all the updates.
Upon rebooting, GDM failed and no amount of command line juju would
bring it back.

Question: should I have just tested the alpha iso as it stands without
the available updates?  This is a new venture for me so please clarify.
Thank you.