Something to consider for sure is the restraints used on each. RNRC utilizes an over the shoulder "horse-collar" restraint where as EE utilizes just a lap bar. Some people prefer the over the shoulder restraint because it makes them feel more "securely" restrained, but others dislike the restraint because if there are any sudden side to side motions, it may result in your head/neck bumping/banging into the restraint. Some people prefer the lap bar restraint because you don't get any of that "head banging" effect and the more open restraint allow for you to more easily turn and look at all the visuals, however others dislike the restraint because (to some) it may not feel "secure" enough or may allow for "too much" movement. (personal preference, I like the lap-bar over the over the shoulder restraint anyday).
Another factor is the ability to "see what's coming up". On RNRC, for the most part, the ride is completely in the dark with specific thematic elements only lighting up as you approach them. Additionally, even if your eyes do adjust enough to be able to make out the rest of the track in the building, it's such a convoluted mess that it's often difficult to expect what's coming next unless you've been on the ride before. For some, this might be a good thing (you can't get scarred/worried if you aren't already worrying about an upcoming element), however, some might really prefer to know in advance what to expect. Fortunately, we live in a technology driven era with plenty of high quality on ride videos of rides which allow you to virtually ride a ride as much as you want before ever hopping on the real ride.
I've been on literally hundreds of roller coasters and (my personal opinion only), I feel that RNRC is the more "extreme" of the two, but not by a huge margin. Both are very fun rides, but if my son was tall enough to ride both and we had to choose which to go on first, I'd pick Everest over RNRC any day...