The Ruger has some non standard parts. I'd go with the Eagle.
kwg
What non-standard parts does the AR 556 have?
The big one that is giving folks some issues is the plastic hand guard ring at the rear of the barrel. If you don't turn it just the right way, it breaks or gets stuck. The other is the front sight. Not a huge issue and it's my understanding it has a commercial butt stock.
The last issue is the price. It's meant to be an entry level rifle sold for around $500. Demand has driven the price to closer to $600 or more. I just don't think the rifle is worth the $600 price tag with non Milspec parts. Demand or no demand. Ruger or no Ruger.
I'm sure there is some issues with the Eagle I would not like as well. Since it's an entry level gun I'm sure there were short cuts but:
The question by the OP was "Ruger or Eagle" I would buy the Eagle and not the Ruger and that's the reasons why.
kwg