Latitude vs. Precision

Some minor points: you have the option of getting the X4500 IGP in the E6400 and you do not have this option in the M4400. For your needs, this IGP should be more than enough; furthermore it will run cooler and give you more battery life. I believe that the M4400 is also slightly heavier due to the fancy lid.

That being said, both are ultimately solid machines, and at the same spec and price point, there isn't a big downside to taking one over the other.

 

the latitude E5x00 series are lower end latitudes though. while still well built, they're heavier and use a polycarbonate chassis vs a magnesium alloy one