Thank you! To be entirely honest knowing which model solution is correct goes beyond my forecasting ability as I don't know enough about the synoptics behind storm formation yet (though I am trying to learn). However, I am generally able to identify which runs are better and why in relation to synoptics. I think the main way that the Euro develops the storm to be weaker lies in it having less favorable interactions with the low pressure up north. Looking just at the GFS to Euro we can see the GFS gets the ULL out of the northeast slightly faster so there is less connection between the waves.
The Euro on the other hand keeps it a little slower with the northern ULL so there is more suppression and reduction in actual ability to form a low.
Though as I said before this is getting to the end of my knowledge so take it with a grain of salt.