But your e71 has constant email connection. Android devices, by default most often, have gmail, calendar, gtalk, market service, and many others I won't list, all constantly in push mode, always listening for updates to the network via the data connection. That's my point in all this, the Google services are very powerful, but that is why all android phones have poor battery life.
My tests I did show me how good the android kernel actually is at battery efficiency.
Hell I actually have in addition to all those services, 2 gmail accounts, 2 calendars, and my corp exchange account.
It goes deeper, but this difference is the cause. If I take it out of the picture, my nexus battery matches my symbian 5800 and n97 mini.