Yes, BUT it is NOT because of bluetooth, the Bose Soundtouch 30 has a latency via LINE-IN, TOO!!!

It seems to be due to a new kind of signal processing Bose uses in the Soundtouch models, regardless of whether you use the Bluetooth function or connect via cable. These models are unusable for live playing.
The Sounddock models as well as the Soundlink models and the WaveRadio don't have such a delay.