The author of the book Swedish Death Metal (clever title isn't it?) talks about the Gothenburg style which ended up dwarfing the Stockholm scene.
It's hard to call bands like Dark Tranquillity and In Flames actual Melodic Death Metal because they are lacking in the Death Metal portion of the name. In fact they are more akin to melodic metal with harsh vocals for the most part. Anyways what ever you call them, the earlier material of both bands is pretty great!