Nexus 4 Review Inconsistencies

I've probably read a dozen reviews (at least) for the Nexus 4 and I've noticed a large discrepancy in the reviewer's 'opinion' of the battery life (As well as, to a lesser extent, some other hardware factors). It ranges from being great to awful. I'm wondering if people think that this is the result of one or multiple of the following:

  • Differing opinion and expectations in what constitutes 'good' battery life.
  • Pre-release software.
  • Actual hardware inconsistencies.

Some Review Examples:

"The performance of the Nexus 4 is a curious thing...Battery life is yet another segment of the performance that's confused us...Regardless, the experience we had with both of our review units is still a stark contrast to the Optimus G" - Engadget

"I usually get about 12-14 hours out of the battery with medium use." - Android Police

"Out and about town, the Nexus 4's battery life was stellar." - Ars

"The poor battery life is perhaps the Nexus 4's biggest weakness." - Tech Hive

"Battery life was also top notch" - The Verge

"I needed a few good charges to get me through the day" - CNET

"The only thing that really gives me pause is battery life. On paper, the 2100 mAh should power it through the day no problem. As it is right now, this is not a phone I could take on a long trip where outlet access is spotty." - Gizmodo

All of these examples combined with the somewhat bizarre benchmark performance scores and (my personal) lack of faith in previous LG hardware has me worried... Thoughts?