I have an ARC Nucleus Gen 1, Nucleus Gen 2, and an Archimedes action. I like all of them. In reality, I'll probably never need the pivoting bolt lever feature on the Archimedes to remove a stuck case from the barrel chamber. That's the only real difference it has over the Nucleus action's.
I bought mine on ARC's Black Friday sale, so the price was less than what I paid for my Nucleus Gen 2 action, that's the only reason I bought it.
As far as fit & finish goes, there are a couple things that I don't like. ARC used the same style of bolt stop / bolt release as the Nucleus Gen 1 action. I've never has any issues with it in my Nucleus, but the knurled knob on the Archimedes was almost impossible to rotate by hand because there's not enough room to get much grip on it, and either the detent on the part is too deep or the spring tension was high to turn the knob.
It was an easy fix, I just took it apart and cut a couple coils off the detent spring. It works just fine now.
I really wonder why ARC didn't use the same bolt stop / bolt release lever that they use on the Nucleus Gen 2 receiver. It's a simple lever, and works great.
There are some milling marks on the top rear section of the receiver (Behind the scope rail) that can be seen if the light is right, but once you mount a scope on it, you really don't notice it.
I think ARC got in a rush to produce these action's when they got over run with order's for them on the sale, and didn't see the issue before they sent the receiver's out to get coated.
Would I buy another Archimedes? Probably not, because I don't see / need anything it does better than the Nucleus in the real world.