rdc85 :
battery life is depends on hardware spec and user usage.. so can not tells much..
Own 2 lenovo lappy and work with 2 dell ones at office...
i can said both are goods brands.. their quality both better than some others brands..
now it back to specific model u looking for,
since some model get cost saving treatment (since their targeted budget market)..
u're right but i handled with dell but felt it's not ok in material issue .. i don't know
i have to choose between dell inspiron i7 4500u and amd 8850m 2GB DDR3 and lenovo i7 4510u+Nvidia gt 840m 4GB DDR3 and i wish i could play new games smoothly with high graphics