I think you'll get more response by posting to the Appliances Forum.

Good luck!

Here is a link that might be useful: Appliances

Thanks
I'll do that

Call them. I had calls returned promptly on a couple of occasions when I was shopping this winter, and then buying early in the spring. Others on the appliance forum have also posted good feedback by phone from BlueStar, from Mandy among others.

There are threads on the appliance forum that discuss some of the differences between the RNB and the RCS, as well as departures from the norm with the Costco (and other special run models) of RCS. The ranges are similar in many respects, and there are threads about "hot-rod" modifications to boost the output of the RCS burners as well (search for these and mojavean). Off the top of my head, I don't recall whether the Costco RCS has a convection oven, but you likely know already. The newer RNB ranges have the high output burners and better insulated oven doors. They also offer a choice of color. With an RNB order, you also have quite a few options when it comes to specifying the details -- for instance, on our 36" RNB, I had them move the left-hand supernova burner from the front to the rear, bringing the simmer burner to the front of the range -- works well for me and the upcharge for the custom arrangement was very small. OTOH, the RCS offers a very attractive option -- an open-burner range that shares many attributes of the RNB at a very big discount.

Response to djg1:

I have been looking at a new stove, and from what I could find the Costco RCS models are the same as those listed from Blue Star website. Also they are extremely well priced here. RCS 30" $2'650 & RCS 36" $$3'465 including taxes and delivery.