Location: The rifle range, or archery range or behind the computer in Alaska
Re: mcmillian or rimrock?
McMillan lover here.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.
I have owned about 5 McMillan's and only one Rimrock (current Borden era). I think the Rimrock is good, but would probably go for the McMillan in preference. I have always had good dealings with McMillan - in fact will order a 6th stock off them in the next few months.
As a general comment, I have had very mixed success in my dealings with many diverse stock makers, but either of the options you list will work very well compared to a lot of other options on the market.