I'm in the same boat here.
I prefered buying Crusade instead, which I find far more interesting in terms of contents.
That being said, I will be buying Free Mars eventually, not just on my top priority list.
Crusade interested me the most out side of my current campaign arc (I'm taking the kids though the 'Fiery Trial' as an A arc and another plot line involving early work by the shadows destroying a Minbari listening post near Za'ha'dhum, and a Dilgar scientist bent on silencing all of space around there to non Shadow comms traffic as a B plot. Initially involving our warrior woman Minbari but quickly engulfing everyone else.
My worry is that the B plot might overwhelm the A plot because it is more immediate to them the the IPX dispensed make work. Balance...balance.