Thinking about CoS as my next army

Hi all.

I have a couple of larger 40K armies, and I recently finished my first AOS army (Sons of Behemat).

I really like the CoS models, and the new Battleforce is callling to me.

My concern with the faction is that, as I understand it, there are a few brand new models, and the rest of the army is older WHFB Empire models. Is that correct?

How do the older models hold up? Is there any resin left in this army?

Would you recommend CoS right now? I’m not concerned about the meta - I know that always changes.