I know that it's officially unsupported, but i thought this might be helpful to someone at some point anyways.
I just had vienna hang on me.
not entirely sure of the cause, I was focused on another app at the time. Last thing i'd done was load an article in the new 'show the page itself' mode (awesome, btw. :-) ), which happened to contain an embedded flash video fwiw.
Vienna Version: 220.127.116.1100 (2600)
Code Type: X86 (Native)
OS Version: Mac OS X 10.6.8 (10K549)
Attached Activity Monitor sample, crash reports.