I preferred the first trailer. It was just a little more cinematic, IMO, perhaps because I am familiar with the history referenced in it, so there was more meaning than just what was shown (these events were covered in the novella, included in the fansite kit (17.7MB) with a summary here, and in Beyond Divinity).
Also, I found the compression artifacts in the clouds at the start of the second trailer a little distracting (though not so much after watching it a few times).