So any time I think about buying such a speaker system for live playing now, I am anxious about a possible delay via cable, but I haven't encountered any like that of the Bose Soundtouch. It's really sad and stupid they are unusable for such a reason.
So I try to find a new speaker on display in a store and perform the following test:
- plug in a mini-jack Y-cable into the output of my soundsource
- connect one end of the Y-cable to the speaker with a mini jack line cable
- connect the other end of the Y-cable to headphones.
Then I can listen to the speaker with one ear and check the direct signal with my headphones on the other ear. In the case of the Soundtouch 30 the signals are completely out of sync, there's a severe echo.

The Marshall Woburn seems to be safe, I read a review of someone playing e-drums via the Woburn.