Its true what they say about these things, they turn adults back into children... This is my third (already owned the Obi Wan Kenobi & Yoda(for the kid) Sabers).
One thing I will say is that the sound modules are in the saber itself, swapping the battery module (which has the speaker built into it) makes no difference to the sound, Darths will sound like Darths even if I put Obi Wans battery pack in.
Makes a huge difference if you buy decent batterys too. Sounds better than my Obi Wan saber but isnt anywhere near as bright.