Mike,
I think you will find a large degree of variation among ICs.
I am not RA, but as an AMB my experience at ICs has been varied, from excellent to awful.
But that's not unique to ICs. I think you'll find variation in most chains.
Your upcoming in NY mentions the Barclay, in comparison to the various Ws there. I think it's hard to compare the two, since they are rather different kinds of hotel. But some of the Ws such as Union Square would be hard to beat. The Barclay has a lot of supporters, but also a fair number of people who swear never to return. There's a thread in this forum.
The Willard in DC is a nice enough property, and centrally located. I've never stayed at the RC Pentagon City, but I see RCs and FSs as being in a different league than ICs.
Since you have a RA cert, why not give it a try and see if you enjoy your IC experiences, and if not, you can always revert back to SPG and Fairmont???

chop