I love it, and I didn't even need to tell it the session I was speaking at, it just knew and told me I was speaking at that session once I logged in. The 'official' SXSW event calendar has always been clunky even as they upgrade every year.

P.S self plug: http://lanyrd.com/2011/sxsw/sctmq/ In one of the new venues at the Hyatt across the river.