whats the difference ? is the mapboard the same ? same terrainmarkers ? same size of the hexagons ? both games compatible from the material ?

BoW inspite of it's BL Game tag is rather different

-The board & terrain tiles are basically the same (but BoW has towns) but BL has  Left/Center/Right divisions of a classic C&C Game.Bow doesn't.

-BoW has Leaders & BL has Heros but they play differently

-Basically the two games although they look alike & feature similiar components play differently( BoW gives you more control over your units & has a number of victory conditions.BL is mainly a kill the enemy to win.

-BoW is based on a The Fire & Ice books & as such has plenty of back story,BL is more generic with no real game world

-Bow has no magic-BL features magic  & has nonhuman races but BoW just has humans

OD

In Battlelore the units are activatived by cards depending on the sections they are in.  This can lead to some careful management of your hand of command cards.  It was also the cause of some criticisms on luck in drawing command cards, however FFG introduced BattleSavvy rules and these do a lot to change the game for the better (imo).  In Westeros the units are activated differently - the section distinction of left, middle and right flanks are gone and the units operate through the leaders on the board.

The dice system of both games is slightly but significantly different, in BL you roll six-sided dice and hit when you roll the enemy banner colour (and sometimes on the bonus strike face), in Westeros the dice are D8s, and the spread of banner colours is different.

These are just some immediate differences in addition to what Old Dwarf notes.  The games really are quite different. 

The games are not compatable, unless you introduce house rules.

Cheers,

Giles.