Question about extras?

[CDinkel91]

I'm starting to buy more and more blu-ray online. Because of this though I often find the listings to be quite bare.

And because blu-rays themselves are becoming bare sometimes I want to be aware of what I'm buying.

For example Amazon has two listings for Once Upon a Time in the West. The pictures look the same but one is far more expensive. Another are these Universal Steelbooks what features do they have and are there extras? I'd rather not have them but if they have more stuff.... I'm just not sure how to properly research it.

A lot of amazon listings just say none under special features and some I know that's not true.