For those on the fence about MCS, I strongly encourage you to try them, particularly on a long road trip.
They help significantly with ass-soreness. No, they are not as good as a shiatsu massage from some dodgy strip-mall massage joint, but they help.
I've generally found the naysayers about any feature to be people who couldn't afford the package that has that feature. We've all heard it: "Just one more part that could fail!!". We've heard it about the moon roofs, about the power boards, about the winches, about the MCS seats, ad nauseum. I have all of the above, and wouldn't own a truck without them. Window regulators are just one more part that could fail - why don't we go in and out of the windows like Dale Earnhardt!?
At the end of the day, MCS is a nice feature. Even if it were to fail, you still have a nicer, more comfortable seat.