I've experienced this only with Audacity, and
it's close to 6
seconds. Stop works ok.
I think as the Audacity code has been reworked during the 1.1 and
1.2-pre series, the lag after clicking play or record has increased -
this is a purely subjective judgement on my part. On my machine its
more like 2 seconds.
I suspect this is to do with improved buffering design, as I very
rarely get any clicks or dropouts now.
Cheers
Daniel