If I'm not mistaken the Dell DJ also uses a li-polymer battery. I wonder what's the secret of the by-all-accounts extraordinary (>15 hr) battery life people are seeing on this player. Is it the battery or the power management? And wasn't our mOS supposed to help out in this regard.
IMO, this is a big advantage that the DJ has over other jukebox player and the one achilles heel (aside from the lack of FM tuner) of the ipod which in its current iteration actually saw a reduction in battery life.
As for gateway player, I wonder if the extra large LCD they are using is a battery drain. Personally, I think most people would have preferred longer battery life to the big screen.