I'm looking at which version to get for the Underworld Awakening 3D Blu-ray release:

The US edition, distributed by Sony
or
The UK edition, distributed by EiV

I heard both have the 2D and 3D version of the movie on one BD Disc and apparently the 2D suffers for it. Some sources say both editions, UK and US, come from the same master.

Any idea if it's worth to drop more money to get the US edition or can I safely buy the (cheaper) UK edition?

Thanks a lot! I'll dig into these reviews before making a decision but it seems at first glance the video quality on both releases is similar and the only difference is between the 3D and 2D-standalone release:
3D combo disc has inferior 2D presentation compared to the standalone 2D Blu-ray, it would seem, in both regions.