I see in your persona logs that there is pre-load was set. This will impact login sped as Persona has to download them when user logs in.
[0][09/21/2011 21:17:15:0268][VPLogonNotify_OnStartShell] Preloaded Files: User: testuser, Session: 1
But yes before this pre-loading, there was almost 4 minutes slow process, after user authenticated which I suspect another software such as anti-virus might scan offline files population.
It is a correct way to disable anti-virus or other software which has filesystem driver to isolate the issue.